Investment Objective

Calamos Laddered S&P 500^® Structured Alt Protection ETF^® (the "Fund") seeks to provide investors with capital appreciation.

Fees and Expenses of the Fund

The following table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund ("Fund Shares"). Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
Management Fees	0.10	%
Distribution and/or Service Fees (12b-1)	0.00	%
Other Expenses	0.00	%
Acquired Fund Fees and Expenses¹	0.69	%
Total Annual Operating Expenses²	0.79	%

1 "Acquired Fund Fees and Expenses" include certain expenses incurred in connection with the Fund's investment in a laddered portfolio of Calamos S&P 500^® Series Structured Alt Protection ETFs^® (the "Underlying ETFs").
2 The Total Annual Fund Operating Expenses in this fee table may not correlate to the expense ratios in the Fund's financial highlights and financial statements because the financial highlights and financial statements reflect only the operating expenses of the Fund and do not include Acquired Fund Fees and Expenses, which are fees and expenses incurred indirectly by the Fund through its investments in certain underlying investment companies.

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs, whether you sell or hold your Fund Shares, would be:

You would pay the following expenses whether you sell or hold your Fund Shares at the end of the period:

One Year				Three Years				Five Years				Ten Years
$	81			$	252			$	439			$	978

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund Shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the example, affect the Fund's performance. During the period from September 9, 2024 (commencement of operations) through July 31, 2025, the Fund's portfolio turnover rate was 18% of the average value of its portfolio.

Principal Investment Strategies

The Fund seeks to achieve its investment objective by providing investors with US large-cap equity market exposure while attempting to limit downside risk through a laddered portfolio of twelve Calamos S&P 500^® Structured Alt Protection ETF^®s (each an "Underlying ETF" and collectively the "Underlying ETFs"). The term "laddered portfolio" refers to the Fund's investment in multiple Underlying ETFs that have target outcome period expiration dates which occur on a rolling, or periodic, basis. See below for a discussion of "target outcome periods" and their meaning within the strategies of the Underlying ETFs. The rolling or "laddered" nature of the investments in the Underlying ETFs creates diversification of investment time period compared to the risk of acquiring or disposing of any one Underlying ETF at any one time. This diversification of investment

time period is intended to mitigate the risk of failing to benefit from the downside protection of a single Underlying ETF due to the timing of investment in such Underlying ETF and the relative price of the reference asset or having limited or no upside potential remaining because of the cap of a single Underlying ETF. The Fund's laddered approach is intended to allow the Fund to continue to benefit from increases in the value of the SPDR^® S&P 500^® ETF Trust ("SPY"), while limiting downside losses. Depending on when the Fund acquires shares of an Underlying ETF, even with a laddered approach, the cap and/or downside protection of an Underlying ETF may be exhausted unless the Fund acquires shares at the beginning of a Target Outcome Period (as defined below). The Fund does not typically buy shares at the beginning of the Target Outcome Period. Unlike the Underlying ETFs, the Fund itself does not pursue a target outcome strategy. The protection is only provided by the Underlying ETFs and the Fund itself does not provide any stated downside protection against losses. The Fund will likely not receive the full benefit of the Underlying ETF downside protections and could have limited upside potential. The Fund's returns are limited by the caps of the Underlying ETFs.

In order to understand the Fund's strategy and risks, it is important to understand the strategies and risks of the Underlying ETFs. See "Additional Information on the Fund's Investment Objective and Strategies" for a discussion of the principal investment strategies of the Underlying ETFs.

Under normal market conditions, the Fund will invest substantially all of its assets in the Underlying ETFs, which seek to provide investors with returns (before fees and expenses) that match the price return of SPY, up to a predetermined upside cap, while providing downside protection (before fees and expenses) against SPY losses, over a defined one-year outcome period. The Fund intends only to acquire shares of Underlying ETFs in the secondary market and will not engage in any principal transactions with the Underlying ETFs. The Fund and each Underlying ETF are advised by Calamos Advisors LLC ("Calamos" or the "Adviser"). PDR Services, LLC ("PDR") serves as SPY's sponsor. The investment objective of SPY is to seek to provide investment results that, before expenses, correspond generally to the price and yield performance of the S&P 500^® Index. See "SPDR^® S&P 500^® ETF Trust" below for more information.

The Underlying ETFs invest substantially all of their assets in FLexible EXchange^® Options ("FLEX Options") on SPY. FLEX Options are customizable exchange-traded option contracts guaranteed for settlement by the Options Clearing Corporation. Each Underlying ETF uses FLEX Options to employ a "target outcome strategy." Target outcome strategies seek to produce pre-determined investment outcomes based upon the performance of an underlying security or index (in this case, SPY). The pre-determined outcomes sought by the Underlying ETFs, which include downside protection against (before fees and expenses) SPY losses and a cap on upside potential, are based on the price return of SPY over an approximate one-year period beginning on the first business day in the month for which each Underlying ETF is named and ending on the last business day of the preceding month in the following year (the "Target Outcome Period"). Each Underlying ETF establishes a new cap annually at the beginning of each Target Outcome Period. See "Capital Protection and Cap" below under "Additional Information About Investment Strategies and Related Risks."

Each Underlying ETF's strategy has been specifically designed to produce the outcomes (before fees and expenses) based upon SPY's returns over the duration of a Target Outcome Period. At the end of each Target Outcome Period, an Underlying ETF's FLEX Options are generally allowed to expire or be sold at or near their expiration, and the proceeds are used to purchase (or roll into) a new set of FLEX Options expiring in approximately one year. This means that approximately every 30 days, one of the Underlying ETFs will undergo a "reset" of its cap and a refresh of its downside protection. The Fund will generally hold one Underlying ETF with FLEX Options expiring within one month, a second Underlying ETF with FLEX Options expiring within two months, a third Underlying ETF with FLEX Options expiring within three months, etc., up to and including twelve months. The rolling or "laddered" nature of the investments in the Underlying ETFs creates diversification of investment time period and market level (meaning the price of SPY at any given time) compared to the risk of acquiring or disposing of any one Underlying ETF at any one time. Because the Fund typically will not acquire shares of the Underlying ETFs on the first day of a Target Outcome Period and may dispose of shares of the Underlying ETFs before the end of the Target Outcome Period, the Fund may experience investment returns that are very different from those that the Underlying ETFs seek to provide. If an Underlying ETF has experienced certain levels of either gains or losses since the beginning of its current Target Outcome Period, there may be little to no ability for the Fund to achieve gains or benefit from the downside protection for the remainder of the Target Outcome Period.

When an investor purchases shares of a single Underlying ETF, his or her potential outcomes are limited by the Underlying ETF's stated cap and downside protection over a defined time period (depending on when the shares were purchased). Alternatively, the Fund's laddered approach provides a diversified exposure to all of the Underlying ETFs in a single investment. By owning a laddered portfolio of Underlying ETFs, the Fund has the ability to continue to benefit from increases in the value of SPY and to provide a level of downside protection as one of the Underlying ETFs will reset its cap and refresh its downside protection every month based on the price of SPY at the time of the reset. In other words, the continual and periodic "refreshing" of the Underlying ETF caps and downside protection at current SPY prices is intended to allow the Fund to continue to benefit from increases in the value of SPY, while limiting downside losses. This approach reduces the risk inherent in the Underlying ETFs of having the upside potential for an entire Target Outcome Period capped out in cases of rapid appreciation of SPY. It also reduces the risk of failing to benefit from an individual Underlying ETF downside protection in cases where SPY has depreciated. Approximately every 30 days, one of the Underlying ETFs will undergo a reset of its cap and a refresh of its downside protection, meaning that investors will have the ability to benefit from any appreciation in SPY for future periods up to the respective caps of the Underlying ETFs and will have the benefit of the downside protection for future periods. A laddered portfolio can diversify timing risk, similar to how laddered bond portfolios seek to manage timing risks for fixed-income investors.

The Fund intends only to acquire shares of Underlying ETFs in the secondary market and will not engage in any principal transactions with the Underlying ETFs. The Fund intends to generally rebalance its portfolio to equal weight (i.e., 8.33% per Underlying ETF) semi-annually. The Fund also will acquire and dispose of Underlying ETFs in connection with the creation and redemption of Creation Units between semi-annual rebalances. In between such rebalances, market movements in the prices of the Underlying ETFs may result in the Fund having temporary larger exposures to certain Underlying ETFs compared to others. Under such circumstances, the Fund's returns would be more greatly influenced by the returns of the Underlying ETFs with the larger exposures. If an over-weighted Underlying ETF underperforms the other Underlying ETFs, the Fund will experience returns that are inferior to those that would have been achieved if the Underlying ETFs were equally weighted. See Significant Exposure Risk below.

The current list of Underlying ETFs in the Fund's portfolio can be found at https://www.calamos.com/capabilities/structured-protection-etfs/. The Fund's website will provide, on a daily basis, the proportion of the Fund's assets invested in each Underlying ETF at any given time. Each Underlying ETF's website provides important information (including Target Outcome Period start and end dates and the cap (both gross and net of fees) and downside protection both at the start of the Underlying ETF's Target Outcome Period and on any particular day relative to the end of the Target Outcome Period).

Although this website information may be useful in understanding the investment strategies of the Underlying ETFs, it is limited in providing an investor of the Fund with all of the risks and potential outcomes associated with an investment in the Underlying ETFs. For example, it does not provide a direct example of your potential investment return in the Fund because of the Fund's laddered exposure to the Underlying ETFs in which each one of the Underlying ETFs will reset its cap and refresh its downside protection annually based on prevailing market conditions.

The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). The Fund's investment strategy may include active and frequent trading. The Fund may not invest 25% or more of the value of its total assets in securities of issuers in any one industry or group of industries except to the extent that the underlying referenced index of the Underlying ETFs invests more than 25% of its assets in an industry or group of industries. This restriction does not apply to obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities, or securities of other investment companies. As of October 9, 2025, SPY had significant investments in information technology companies.

Principal Risks

An investment in the Fund is subject to risks, and you could lose money on your investment in the Fund. There can be no assurance that the Fund will achieve its investment objective. You should not consider investing in the Fund if your investment objective differs from the Fund's investment objective or if you are not willing to accept the principal risks associated with an

investment in the Fund. The risks associated with an investment in the Fund can increase during times of significant market volatility. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks are presented in alphabetical order to facilitate finding particular risks and comparing them with other funds. Each risk summarized below is considered a "principal risk" of investing in the Fund, regardless of the order in which it appears. The principal risks of investing in the Fund include:

• Absence of an Active Market Risk — The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market makers or authorized participants. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares and market makers are under no obligation to make a market in the Fund's shares. Additionally, only a limited number of institutions act as authorized participants for the Fund and only an authorized participant may engage in creation or redemption transactions directly with the Fund and are not obligated to submit purchase or redemption orders for Creation Units. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund's portfolio securities and the Fund's market price. Any trading halt or other problem relating to the trading activity of these market makers or any issues disrupting the authorized participants' ability to proceed with creation and/or redemption orders could result in a dramatic change in the spread between the Fund's net asset value and the price at which the Fund's shares are trading on the Exchange, which could result in a decrease in value of the Fund's shares. This reduced effectiveness could result in Fund shares trading at a premium or discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

• Authorized Participant Concentration Risk — Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem, Fund Shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

• Cap Change Risk — A new Underlying ETF cap is established at the beginning of each Target Outcome Period and is dependent on prevailing market conditions. As a result, a cap may rise or fall from one Target Outcome Period to the next and is unlikely to remain the same for consecutive Target Outcome Periods.

• Capped Upside Risk — Each Underlying ETF's strategy seeks to provide returns (before fees and expenses) that match the price return of SPY for shares acquired on the first day of a Target Outcome Period and held for the entire Target Outcome Period, subject to a pre-determined upside cap. Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each semi-annual rebalance, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each semi-annual rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period. In the event that the Fund acquires Underlying ETF shares after the first day of a Target Outcome Period and the Underlying ETF has risen in value to a level near or at the cap (because the Fund's potential gain will be limited to the difference between the Underlying ETF's NAV on the date the Fund purchases Underlying ETF shares and the cap), there may be little or no ability for the Fund to experience an investment gain on its shares, however, the Fund will remain vulnerable to downside risks. This could be true for all of the Underlying ETFs held by the Fund at a certain point in time severely limiting the Fund's ability to participate in gains during that time. If SPY experiences gains during a Target Outcome Period, an Underlying ETF will not participate in those gains beyond the cap. If the Fund buys Underlying ETF shares when the price exceeds the cap, the Fund will not experience any gain regardless of the performance of SPY.

• Cash Holdings Risk — To the extent the Fund holds cash positions, the Fund risks achieving lower returns and potential lost opportunities to participate in market appreciation which could negatively impact the Fund's performance and ability to achieve its investment objective.

• Costs of Buying and Selling Fund Shares — Due to the costs of buying or selling Fund Shares, including brokerage commissions imposed by brokers and bid/ask spreads, frequent trading of Fund Shares may significantly reduce investment results and an investment in Fund Shares may not be advisable for investors who anticipate regularly making small investments.

• Counterparty Risk — Underlying ETF transactions involving a counterparty are subject to the risk that the counterparty will not fulfill its obligation to the Underlying ETF. Counterparty risk may arise because of the counterparty's financial condition (i.e., financial difficulties, bankruptcy, or insolvency), market activities and developments, or other reasons, whether foreseen or not. A counterparty's inability to fulfill its obligation may result in significant financial loss to an Underlying ETF and, in turn, the Fund. An Underlying ETF may be unable to recover its investment from the counterparty or may obtain a limited recovery, and/or recovery may be delayed. The OCC acts as guarantor and central counterparty with respect to the FLEX Options. As a result, the ability of an Underlying ETF to meet its objective depends on the OCC being able to meet its obligations. In the unlikely event that the OCC becomes insolvent or is otherwise unable to meet its settlement obligations, an Underlying ETF and, in turn, the Fund could suffer significant losses.

• Derivatives Risk — Derivatives are instruments, such as options, futures and forward foreign currency contracts, whose value is derived from that of other assets, rates or indices. The use of derivatives for non-hedging purposes may be considered more speculative than other types of investments. Derivatives can be used for hedging (attempting to reduce risk by offsetting one investment position with another) or non-hedging purposes. Hedging with derivatives may increase expenses, and there is no guarantee that a hedging strategy will work. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. In addition, derivative instruments are subject to counterparty risk, meaning that the party with whom the Fund enters into a derivative transaction may experience a significant credit event and/or may be unwilling or unable to make timely settlement payments or otherwise honor its obligations. Changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index, and the Fund could lose more than the principal amount invested.

• Equity Securities Risk — The securities markets are volatile, and the market prices of the SPY's securities may decline generally. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions. If the market prices of the securities owned by the SPY fall, the value of your investment in the Fund will decline.

• Flex Options Risk — The Underlying ETFs invest in FLEX Options. Trading FLEX Options involves risks different from, or possibly greater than, the risks associated with investing directly in securities. The Underlying ETFs may experience substantial downside from specific FLEX Option positions and certain FLEX Option positions may expire worthless. The FLEX Options are listed on an exchange; however, no one can guarantee that a liquid secondary trading market will exist for the FLEX Options. In the event that trading in the FLEX Options is limited or absent, the value of the Underlying ETFs' FLEX Options may decrease. In a less liquid market for the FLEX Options, liquidating the FLEX Options may require the payment of a premium (for written FLEX Options) or acceptance of a discounted price (for purchased FLEX Options) and may take longer to complete. A less liquid trading market may adversely impact the value of the FLEX Options and Underlying ETFs' shares and result in the Underlying ETFs and, in turn, the Fund being unable to achieve their investment objective. Less liquidity in the trading of the Underlying ETF's FLEX Options could have an impact on the prices paid or received by the Underlying ETFs for the FLEX Options in connection with creations and redemptions of the Underlying ETF's shares. Depending on the nature of this impact to pricing, an Underlying ETF may be forced to pay more for redemptions (or receive less for creations) than the price at which it currently values the FLEX Options. Such overpayment or under collection may impact the value of the Underlying ETF and whether the Underlying ETF can satisfy its investment objective. Additionally, in a less liquid market for the FLEX Options, the liquidation of a large number of options may more significantly impact the price. A less liquid trading market may adversely impact the value of the FLEX Options and

the value of the Underlying ETFs. The trading in FLEX Options may be less deep and liquid than the market for certain other exchange-traded options, non-customized options or other securities.

• Flex Options Valuation Risk — The FLEX Options held by the Underlying ETFs will be exercisable at the strike price only on their expiration date. Prior to the expiration date, the value of the FLEX Options will be determined based upon market quotations or using other recognized pricing methods. The FLEX Options are also subject to correlation risk, meaning the value of the FLEX Options does not increase or decrease at the same rate as SPY (although they generally move in the same direction) or its underlying securities. The value of the FLEX Options prior to the expiration date may vary because of factors other than the value of SPY, such as interest rate changes, changing supply and demand, decreased liquidity of the FLEX Options, a change in the actual and perceived volatility of the stock market and SPY and the remaining time to expiration. FLEX Option prices may also be highly volatile and may fluctuate substantially during a short period of time. During periods of reduced market liquidity or in the absence of readily available market quotations for the holdings of the Underlying ETFs, the ability of the Underlying ETFs to value the FLEX Options becomes more difficult and the judgment of the Underlying ETFs' investment adviser (employing the fair value procedures approved by the Board of Trustees of the Trust) may play a greater role in the valuation of the Underlying ETFs' holdings due to reduced availability of reliable objective pricing data. Consequently, while such determinations may be made in good faith, it may nevertheless be more difficult for the Underlying ETFs to accurately assign a daily value. Under those circumstances, the value of the FLEX Options will require more reliance on the investment adviser's judgment than that required for securities for which there is an active trading market. This creates a risk of mispricing or improper valuation of the FLEX Options which could impact the value paid for shares of the Underlying ETFs.

• Fund-of-Funds Risk — Shareholders of the Fund will experience investment returns that are different than the investment returns provided by an Underlying ETF. The Fund does not itself pursue a defined outcome strategy, nor does the Fund itself provide downside protection against SPY losses. Because the Fund will typically not purchase an Underlying ETF on the first day of a Target Outcome Period, it is not likely that the stated outcome of the Underlying ETF will be realized by the Fund. The Fund will be continuously exposed to the investment profiles of each of the Underlying ETFs during their respective Target Outcome Periods. The Fund, with its aggregate exposure to each of the Underlying ETFs, may have investment returns that are inferior to that of any single Underlying ETF or group of Underlying ETFs over any given time period. In between the semi-annual rebalance period of the Index, because the Fund is not equally weighted on a continuous basis, the Fund may be exposed to one or more Underlying ETFs disproportionately when compared to other Underlying ETFs. In such circumstances, the Fund will be subject to the over-weighted performance of such Underlying ETF. As a shareholder in other ETFs, the Fund bears its proportionate share of each ETF's expenses, subjecting Fund shareholders to duplicative expenses.

• Index or Model Constituent Risk — The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund's shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund's net asset value could be negatively impacted and the Fund's market price may be below the Fund's net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

• Information Technology Companies Risk — SPY invests significantly in information technology companies. Information technology companies produce and provide hardware, software and information technology systems and services. These companies may be adversely affected by rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, the loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards and frequent new product introductions. In addition, information technology companies are particularly vulnerable to federal, state and local government regulation, and competition and consolidation, both domestically and internationally, including competition from foreign competitors with lower production costs. Information technology companies also heavily rely on intellectual property rights and may be adversely affected by the loss or impairment of those rights.

• Large Capitalization Companies Risk — SPY invests in the securities of large capitalization companies. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

• Management Risk — The Fund is subject to management risk because it is an actively managed portfolio. In managing the Fund's investment portfolio, the portfolio managers will apply investment techniques and risk analyses that may not produce the desired result. There can be no guarantee that the Fund will meet its investment objective.

• Market Fluctuation Tax Risk and Cash Transaction Risk — The Fund is acquiring shares of the Underlying ETFs in the open market. When the Fund sells shares of the Underlying ETFs in the open market, the Fund will recognize gain or loss on the disposition of the shares, which could have a negative impact on Fund returns. In addition, note that the Fund may, under certain circumstances, effect a portion of its creations and redemptions for cash rather than in-kind. If the Fund effects redemptions for cash, it may be required to sell shares of the Underlying ETFs in order to obtain the cash needed to distribute redemption proceeds. Any recognized gain on these sales by the Fund will generally cause the Fund to recognize a gain it might not otherwise have recognized, or to recognize such gain sooner than would otherwise be required if it were to distribute such shares only in-kind. The Fund intends to distribute these gains to shareholders to maintain its qualification as a RIC and avoid a fund-level tax. As a result, shareholders may receive a larger amount of, or accelerated, taxable distributions from the Fund than if the Fund did not employ such a strategy. Moreover, cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. These brokerage fees and taxes, which will be higher than if the Fund sold and redeemed its shares entirely in-kind, will be passed on to those purchasing and redeeming Creation Units in the form of creation and redemption transaction fees. In addition, these factors may result in wider spreads between the bid and the offered prices of the Fund's shares than for ETFs that distribute portfolio securities in-kind. The Fund's use of cash for creations and redemptions could also result in dilution to the Fund and increased transaction costs, which could negatively impact the Fund's ability to achieve its investment objective.

• Market Risk — The risk that the securities markets will increase or decrease in value is considered market risk and applies to any security. If there is a general decline in the stock or fixed-income market, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests.

• New Fund Risk — The Fund is a recently organized investment company with a limited operating history. As a result, prospective investors have a limited track record or history on which to base their investment decision.

• Non-Diversification Risk — The Fund is classified as "non-diversified" under the 1940 Act. As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly invested in certain issuers.

• Operational Risk — The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund's ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

• Options Risk — The use of options by the Underlying ETFs involves investment strategies and risks different from those associated with ordinary portfolio securities transactions and depends on the ability of the Underlying ETFs' portfolio managers to forecast market movements correctly. The prices of options are volatile and are influenced by, among other things, actual and anticipated changes in the value of the underlying instrument, or in interest or currency exchange rates, including the anticipated volatility, which in turn are affected by fiscal and monetary policies and by national and

international political and economic events. The effective use of options by the Underlying ETFs also depends on the Underlying ETFs' ability to terminate option positions at times deemed desirable to do so. There is no assurance that the Underlying ETFs will be able to effect closing transactions at any particular time or at an acceptable price. In addition, there may at times be an imperfect correlation between the movement in values of options and their underlying securities and there may at times not be a liquid secondary market for certain options.

• Premium/Discount Risk — The market price of the Fund's shares will generally fluctuate in accordance with changes in the Fund's net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund's investment advisor cannot predict whether shares will trade below at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund's investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund's shares may become less liquid in response to deteriorating liquidity in the market for the Fund's underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund's shares and their net asset value and the bid/ask spread on the Fund's shares may widen.

• Sector Risk — To the extent the SPY invests a significant portion of its assets in a particular sector, a greater portion of the Underlying ETF's and Fund's performance may be affected by the general business and economic conditions affecting that sector. Each sector may share economic risk with the broader market, however there may be economic risks specific to each sector. As a result, returns from those sectors may trail returns from the overall stock market, and it is possible that the SPY may underperform the broader market.

• Significant Exposure Risk — The Fund intends to generally rebalance its portfolio to equal weight (i.e., 8.33% per Underlying ETF) semi-annually, in connection with the reset of each Underlying ETF. In between such rebalances, market movements in the prices of the Underlying ETFs may result in the Fund having temporary larger exposures to certain Underlying ETFs compared to others. Under such circumstances, the Fund's returns would be more greatly influenced by the returns of the Underlying ETFs with the larger exposures.

• SPY Equity Risk — Because each Underlying ETF holds FLEX Options that reference SPY, each Underlying ETF has exposure to the equity securities markets. Equity securities prices fluctuate for several reasons, including changes in investors' perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

• SPY Risk — Each Underlying ETF invests in FLEX Options that reference SPY, which subjects the Underlying ETFs to certain of the risks of owning shares of an ETF as well as the types of instruments in which SPY invests. The value of SPY will fluctuate over time based on fluctuations in the values of the securities held by SPY, which may be affected by changes in general economic conditions, expectations for future growth and profits, interest rates and the supply and demand for those securities. In addition, ETFs are subject to absence of an active market risk, premium/discount risk and trading issues risk. Brokerage, tax and other expenses may negatively impact the performance of the Underlying ETF and, in turn, the value of the Fund's shares. An ETF that tracks an index may not exactly match the performance of the index due to cash drag, differences between the portfolio of the ETF and the components of the index, expenses and other factors.

• Target Outcome Period Risk — Each Underlying ETF's investment strategy is designed to deliver returns that match the price return of SPY if shares are bought on the day on which the Underlying ETF enters into the FLEX Options (i.e., the first day of a Target Outcome Period) and held until those FLEX Options expire at the end of the Target Outcome Period

subject to the cap. Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each semi-annual rebalance, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each semi-annual rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period. In the event the Fund acquires shares after the first day of a Target Outcome Period or disposes of shares prior to the expiration of the Target Outcome Period, the value of the Fund's investment in Underlying ETF shares may not be protected against a decline in the value of SPY and may not participate in a gain in the value of SPY for the Fund's investment period.

• Tax Risk from Investment in Other Investment Companies — The Fund and each Underlying ETF intend to elect and to qualify each year to be treated as a "regulated investment company" ("RIC") under Subchapter M of the Code. The federal income tax treatment of certain aspects of each Underlying ETF's operations — including its options strategy, its hedging strategy, and the possible application of the "straddle" rules and various loss limitations — is not entirely clear or may be subject to recharacterization by the Internal Revenue Service. It could be more difficult to comply with the tax requirements applicable to RICs if the tax characterization of investments or the tax treatment of the income from such investments were successfully challenged by the Internal Revenue Service. Any such failure to comply with the rules applicable to RICs could cause an Underlying ETF to fail to qualify as such. If an Underlying ETF were to fail to qualify as a RIC for purposes of the Code, the Fund may not meet the diversification tests necessary to qualify as a RIC and thus may lose its own RIC status. If the Fund did not qualify as a RIC for any taxable year and certain relief provisions were not available, the Fund's taxable income would be subject to tax at the Fund level and to a further tax at the shareholder level when such income is distributed. In such event, in order to requalify for taxation as a RIC, the Fund might be required to recognize unrealized gains, pay substantial taxes and interest and make certain distributions. This would cause investors to incur higher tax liabilities than they otherwise would have incurred and would have a negative impact on Fund returns. In such event, the Fund's Board of Trustees may determine to reorganize or close the Fund or materially change the Fund's investment objective and strategies. In the event that the Fund fails to qualify as a RIC, the Fund will promptly notify shareholders of the implications of that failure.

• Trading Issues Risk — Trading in Fund Shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in Fund Shares inadvisable. In addition, trading in Fund Shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange's "circuit breaker" rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund's assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

• Underlying ETF Concentration Risk — An Underlying ETF may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Underlying ETF's investments more than the market as a whole, to the extent that the Underlying ETF's investments are concentrated in the securities and/or other assets of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector, market segment or asset class.

• Underlying ETF Exposure Risk — An investment in the Fund may provide returns that are lower than the returns that an investor could achieve by investing in one or more of the Underlying ETFs alone. Additionally, if one or more of the Underlying ETFs has exceeded its cap at the time that you invest in the Fund, you may derive no benefit from the Fund's investment in that Underlying ETF until the next reset of the Underlying ETF. Likewise, if one or more of the Underlying ETFs has decreased in value below its downside protection at the time that you invest in the Fund, you may derive no downside protection from the Fund's investment in that Underlying ETF. See Capital Protection Risk and Capped Upside Risk above. As a shareholder in other ETFs, the Fund bears its proportionate share of each ETF's expenses, subjecting Fund shareholders to duplicative expenses. The Fund does not itself pursue a target outcome strategy and does not provide any downside protection against Underlying ETF losses.

• Underlying ETF Risk — The Fund's investment in shares of the Underlying ETFs subjects it to the risks of owning the securities held by the Underlying the ETF, as well as the same structural risks faced by an investor purchasing shares of the

Fund, including absence of an active market risk, premium/discount risk and trading issues risk. As a shareholder in another ETF, the Fund bears its proportionate share of the ETF's expenses, subjecting Fund shareholders to duplicative expenses.

Fund Performance

The Fund commenced operations on September 9, 2024, and thus does not yet have annual returns for a full calendar year. Accordingly, performance data is not included. Performance information is available at no cost by visiting www.calamos.com. Past performance (before and after taxes) is not an indication of future performance.

Investment Adviser

Calamos Advisors LLC ("Calamos Advisors" or the "Adviser")

Portfolio Managers

PORTFOLIO MANAGER/ FUND TITLE (IF APPLICABLE)	PORTFOLIO MANAGER EXPERIENCE IN THE FUND	PRIMARY TITLE WITH ADVISER
David O'Donohue	Since September 2024	SVP, Sr. Co-Portfolio Manager
Jimmy Young	Since September 2024	SVP, Co-Portfolio Manager
Eli Pars	Since September 2024	SVP, Sr. Co-Portfolio Manager
Jason Hill	Since September 2024	SVP, Sr. Co-Portfolio Manager
Anthony Vecchiolla	Since September 2024	VP, Co-Portfolio Manager
Jordan Rosenfeld	Since November 2025	VP, Co-Portfolio Manager

Portfolio Holdings. The Fund's portfolio holdings are disclosed on its website daily after the close of trading on the Exchange and prior to the opening of trading on the Exchange the following day. A description of the Fund's policies and procedures with respect to the disclosure of such Fund's portfolio holdings is available in the Fund's Statement of Additional Information ("SAI").

Premium/Discount Information. Information about the premiums and discounts at which the Fund's Shares have traded will be available at www.calamos.com.

Purchase and Sale of Fund Shares

The Fund will issue (or redeem) Fund Shares to certain institutional investors (typically market makers or other broker-dealers) only in large blocks of Fund Shares known as "Creation Units." Creation Unit transactions are conducted in exchange for the deposit or delivery of a designated portfolio of in-kind securities and/or cash.

Individual Fund Shares may only be purchased and sold on the Exchange, other national securities exchanges, electronic crossing networks and other alternative trading systems through your broker-dealer at market prices. Because Fund Shares trade at market prices rather than at net asset value ("NAV"), Fund Shares may trade at a price greater than NAV (premium) or less than NAV (discount). When buying or selling Fund Shares in the secondary market, you may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase Fund Shares (bid) and the lowest price a seller is willing to accept for Fund Shares (ask) (the "bid-ask spread"). Recent information regarding the Fund's NAV, market price, premiums and discounts, and bid-ask spreads is available at https://www.calamos.com/.

Tax Information

Net investment income and capital gains distributions you receive from the Fund generally are subject to federal income taxes and may also be subject to state and local taxes. The Fund intends to distribute net investment income and capital gains, if any, at least annually.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer or other financial intermediary (such as a bank), such Fund and its related companies may pay the intermediary for the sale of Fund Shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary's website for more information.

The Fund is a series of Calamos ETF Trust and is regulated as an "investment company" under the 1940 Act. The Fund is actively managed and does not seek to track the performance of an index. The Fund's investment objective to seek to provide investors with capital appreciation is non-fundamental and may be changed by the Board of Trustees of the Trust (the "Board") without shareholder approval. Unless an investment policy is identified as being fundamental, all investment policies included in this prospectus and the Fund's Statement of Additional Information ("SAI") are non-fundamental and may be changed by the Board without shareholder approval. If there is a material change to the Fund's principal investment strategies, you should consider whether the Fund remains an appropriate investment for you. There is no guarantee that the Fund will achieve its investment objective.

The Fund is classified as "non-diversified" under the 1940 Act, as amended. The Fund's investment strategy may include active and frequent trading. The Fund may not invest 25% or more of the value of its total assets in securities of issuers in any one industry or group of industries except to the extent that the underlying referenced index of the Underlying ETFs invests more than 25% of its assets in an industry or group of industries. This restriction does not apply to obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities, or securities of other investment companies.

Under normal market conditions, the Fund will invest at least 80% of its net assets (plus any borrowings for investment purposes) in ETFs. Shareholders will be provided with 60-day written notice of any change to this policy.

The Fund may invest in ETFs in excess of the limits imposed under the 1940 Act on investments in other investment companies. Accordingly, the Fund intends to rely on Section 12(d)(1)(G) of the 1940 Act in connection with such investments.

By investing substantially all of its assets in the Underlying ETFs, the Fund seeks to provide upside participation (before fees and expenses) in the price return of SPY, while attempting to limit downside risk (due to the downside protection provided for in each of the Underlying ETFs). Each Underlying ETF's strategy has been specifically designed to produce the outcomes based upon SPY's price returns over the duration of a Target Outcome Period. At the end of each Target Outcome Period, an Underlying ETF's FLEX Options are generally allowed to expire or sold at or near their expiration, and the proceeds are used to purchase (or roll into) a new set of FLEX Options expiring in approximately one year. This means that approximately every 30 days, one of the Underlying ETFs will undergo a "reset" of its cap and a refresh of its downside protection. At any given time, once fully implemented, the Fund will generally hold one Underlying ETF with FLEX Options expiring within one month, a second Underlying ETF with FLEX Options expiring within two months, a third Underlying ETF with FLEX Options expiring within three months, etc., up to and including twelve months. The rolling or "laddered" nature of the Underlying ETFs creates diversification of investment time period and market level compared to the risk of acquiring or disposing of any one Underlying ETF at any one time.

When an investor purchases shares of a single Underlying ETF, his or her potential outcomes are limited by the Underlying ETF's stated cap and downside protection over a defined time period (depending on when the shares were purchased). Alternatively, the Fund's laddered approach provides a diversified exposure to all of the Underlying ETFs in a single investment. By owning a laddered portfolio of Underlying ETFs, the Fund has the ability to continue to benefit from increases in the value of SPY and to provide a level of downside protection as one of the Underlying ETFs will reset its cap and refresh its downside protection every month based on the price of SPY at the time of the reset. In other words, the continual and periodic "refreshing" of the Underlying ETF caps and downside protections at current SPY prices is intended to allow the Fund to continue to benefit from increases in the value of SPY, while limiting downside losses. This approach reduces the risk inherent in the Underlying ETFs of having the upside potential for an entire Target Outcome Period capped out in cases of rapid appreciation of SPY. It also reduces the risk of failing to benefit from an individual Underlying ETF's downside protection in cases where SPY has depreciated. Approximately every 30 days, one of the Underlying ETFs will undergo a reset of its cap and a refresh of its downside protection, meaning that investors will have the ability to benefit from any appreciation in SPY for future periods up to the respective caps of the Underlying ETFs and will have the benefit of the downside protection for future periods. A laddered portfolio can diversify the timing risk, similar to how laddered bond portfolios seek to manage timing risks for

fixed-income investors. Unlike the Underlying ETFs, the Fund itself does not pursue a target outcome strategy. The downside protection is only provided by the Underlying ETFs and the Fund itself does not provide any stated downside protection against losses. The Fund will likely not receive the full benefit of the Underlying ETF downside protection and could have limited upside potential. The Fund's returns are limited by the caps of the Underlying ETFs.

The target outcomes each Underlying ETF seeks for investors that hold its shares for an entire Target Outcome Period are as follows, though there can be no guarantee these results will be achieved:

• If SPY appreciates over the Target Outcome Period, the combination of FLEX Options held by the Underlying ETF seeks to provide upside participation (before the Underlying ETF's fees and expenses) matching that of the price return of SPY, up to a cap that is determined at the start of the Target Outcome Period.

• If SPY decreases over the Target Outcome Period, the combination of FLEX Options held by the Underlying ETF seeks to provide downside protection of the of SPY losses, prior to taking into account the Underlying ETF's fees and expenses.

Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each semi-annual rebalance, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period and therefore is likely to experience investment returns very different from those that the Underlying ETF seeks to provide. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each semi-annual rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period, and therefore the Fund is likely to experience investment returns very different from those that the Underlying ETFs seek to provide. The Fund will likely not receive the full benefit of the Underlying ETF downside protection and could have limited upside potential. When the Fund acquires and disposes of shares of the Underlying ETFs in between semi-annual rebalances in connection with the creation and redemption of creation units, it will acquire such shares pro-rata based on the then current weightings of the Underlying ETFs in the Fund's portfolio.

The Underlying ETFs

On the first day of each new Target Outcome Period, an Underlying ETF resets by investing in a new set of FLEX Options that are designed to provide a new cap for the new Target Outcome Period. This means that each Underlying ETF's cap will change for each Target Outcome Period based upon prevailing market conditions at the beginning of each Target Outcome Period. Each Underlying ETF will be perpetually offered and not terminate after the initial or any subsequent Target Outcome Period. Approximately one week prior to the end of the current Target Outcome Period, the Underlying ETF's website will be updated to alert existing shareholders that the Target Outcome Period is approaching its conclusion and will disclose the anticipated cap range for the next Target Outcome Period.

While the cap and downside protection of an Underlying ETF provide the intended outcomes only for investors that hold their shares throughout the complete term of the Target Outcome Period, an investor, like the Fund, can expect their shares to generally move in the same direction as SPY during a Target Outcome Period. However, during a Target Outcome Period, an investor's shares may not experience price movement to the same extent as the price movement of SPY. During a Target Outcome Period there may be periods of significant disparity between an Underlying ETF's NAV and the price performance of SPY. As SPY's price and the Underlying ETF's NAV change over a Target Outcome Period, an investor, like the Fund, acquiring shares after the start of a Target Outcome Period will likely have a different return potential than an investor who purchased shares at the start of the Target Outcome Period. This is because while the cap and downside protection for a Target Outcome Period are fixed levels that are calculated in relation to the SPY price and the Underlying ETF's NAV at the start of a Target Outcome Period and that remain constant throughout the Target Outcome Period, an investor, like the Fund, purchasing shares at market value during a Target Outcome Period likely purchased shares at a price that is different from the Underlying ETF's NAV at the start of the Target Outcome Period (i.e., the NAV that the cap and downside protection reference). For example, if the Fund acquires shares of an Underlying ETF during a Target Outcome Period at a time when the Underlying ETF has decreased in value from its value on the first day of the Target Outcome Period, the Fund's downside protection will essentially be decreased by the amount of the decrease in the Underlying ETF's

value. Conversely, if the Fund acquires shares of an Underlying ETF during a Target Outcome Period at a time when the Underlying ETF has increased in value from its value on the first day of the Target Outcome Period, the cap for that portion of the Fund's portfolio will essentially be decreased by the amount of the increase in the Underlying ETF's value. See "Capital Protection and Cap" below for additional information. In addition, the current price of SPY is likely to be different from the price of SPY at the start of a Target Outcome Period, meaning the Fund may not experience the intended return of an Underlying ETF.

Capital Protection and Cap

Each Underlying ETF seeks to provide capital protection to absorb 100% of losses (before fees and expenses) of the SPY at the end of each Outcome Period. Each Underlying ETF's capital protection level will be reduced by the Underlying ETF's management fees and further reduced by any brokerage commissions, trading fees, taxes and extraordinary expenses not included in the Underlying ETF's management fee. If the Underlying ETF is required to increase its holdings of cash during the Outcome Period to pay fees and expenses incurred by it, the capital protection level may be further reduced. The Underlying ETFs do not seek to provide capital protection against 100% of losses (before fees and expenses) of such Underlying ETF as of any time other than the end of the Outcome Period.

Depending on the Underlying ETF's NAV at the time of purchase, the Fund may lose its entire investment in an Underlying ETF. An investment in the Fund is only appropriate for shareholders willing to bear those losses. Despite the intended downside protection of the Underlying ETFs, the Fund could lose its entire investment.

The returns of each Underlying ETF are subject to a cap for each Target Outcome Period. Unlike other investment products, the potential returns the Fund can receive from an Underlying ETF are subject to a pre-determined upside return cap that represents the maximum percentage return the Fund can achieve from an investment in the Underlying ETF for an entire Target Outcome Period. In the event SPY experiences gains over a Target Outcome Period, the Underlying ETF seeks to provide investment returns before fees and expenses that match the percentage increase of SPY, but any percentage gains over amount of the cap will not be experienced by the Underlying ETF or, in turn, the Fund. This means that if SPY experiences gains for a Target Outcome Period in excess of the cap for that Target Outcome Period, neither the Underlying ETF nor the Fund will benefit from those excess gains. Additionally, if a Target Outcome Period has begun and an Underlying ETF has increased in value to a level near to the cap, an investor, like the Fund, purchasing at that price has little or no ability to achieve gains but remains vulnerable to downside risks. Therefore, regardless of the performance of SPY, the cap is the maximum return the Fund can achieve from an investment in the Underlying ETF for that Target Outcome Period.

Each Underlying ETF's cap is set on the first day of each Target Outcome Period. The defined cap applicable to a Target Outcome Period will vary based on prevailing market conditions at the time, including then-current interest rate levels, SPY volatility, and the relationship of puts and calls on the underlying FLEX Options.

The cap level is a result of the design of each Underlying ETF's principal investment strategy. In order to provide the downside protection, the Underlying ETF purchases a series of put and call FLEX Options on the first day of a Target Outcome Period. As the purchaser of these FLEX Options, the Underlying ETF is obligated to pay a premium to the seller of those FLEX Options. The portfolio managers calculate the amount of premiums that the Underlying ETF will owe on the put options acquired and sold to provide the downside protection and will then go into the market and sell call options with terms that entitle the Underlying ETF to receive premiums such that the net amount of premiums paid per unit of SPY is approximately equal to the price per unit of shares of SPY. The cap is the strike price of those sold FLEX Options.

The following line graph and bar chart illustrate the hypothetical returns that the FLEX Options seek to provide for each Underlying ETF with respect to the price performance of SPY in certain illustrative scenarios over the course of a Target Outcome Period. The caps in the line graph and bar chart below are for illustration only and the actual caps may be different.

The line graph and bar chart do not take into account payment by the Underlying ETFs of fees and expenses. There is no guarantee that an Underlying ETF will be successful in providing these investment outcomes for any Target Outcome Period.

• The line graph above represents the Underlying ETF's hypothetical intended return profile based upon the performance of SPY.

• The cap in the line graph above is for illustration only and the actual caps may be different.

Explanation of diagram:

1. Calamos S&P 500^® Structured Alt Protection ETF^® — Participation Layer: The dotted grey line represents the first layer, which involves purchasing a near zero-strike (i.e., deep in-the-money) call on the reference asset, at a pre-determined strike to provide full participation to the price return of the underlying reference asset. In other words, the full price participation provided by this layer provides potential gains and losses that are tantamount to that of owning the underlying reference asset outright, except that this layer does not participate in the dividend yield of the underlying reference asset.

2. Capital Protection Layer: The solid grey line represents the second layer, which involves purchasing an at-the-money put option, which produces protection equal to 100% of losses (before fees and expenses) of the price return of the reference asset, over the Outcome Period.

3. Upside Participation Layer (the "Cap"): The solid black line illustrates the final layer, which involves selling an out-of-the-money call, thereby creating the upside cap. The strike price at which the call is sold is determined so that the combined net options purchase price is approximately equal to the underlying asset's current value. The cost of this layer is a credit equal to the price that would make the total package "no-cost" or fully financed.

Investors, like the Fund, purchasing shares of an Underlying ETF during a Target Outcome Period will experience different results.

General Information about FLEX Options

FLEX Options are customizable exchange-traded option contracts guaranteed for settlement by the Options Clearing Corporation ("OCC"). The OCC guarantees performance by each of the counterparties to the FLEX Options, becoming the "buyer for every seller and the seller for every buyer," with the goal of protecting clearing members and options traders from counterparty risk. The OCC may make adjustments to FLEX Options for certain significant events, as more fully described in the Fund's Statement of Additional Information. Although guaranteed for settlement by the OCC, FLEX Options are still subject to counterparty risk with the OCC and subject to the risk that the OCC may fail to perform the settlement of the FLEX Options due to bankruptcy or other adverse reasons. The FLEX Options that the Underlying ETFs will hold that reference SPY will give the Underlying ETFs the right or the obligation to either receive or deliver shares of SPY, or the right or the obligation to either receive or deliver a cash payment on the option expiration date based upon the difference between the SPY's value and a strike price, depending on whether the option is a put or call option and whether the Underlying ETF purchases or sells the option. The FLEX Options held by the Underlying ETFs are European style options, which are exercisable at the strike price only on the FLEX Option expiration date. The Underlying ETFs will generally, under normal conditions, hold FLEX Options for each Outcome Period. The Underlying ETFs will purchase call options (giving the Underlying ETFs the right to receive shares of SPY or a cash payment) and put options (giving the Underlying ETF the right to deliver shares of SPY or a cash payment), while simultaneously selling (i.e., writing) call options (giving the Underlying ETF the obligation to deliver shares of SPY or a cash payment). The Underlying ETFs intend to structure the FLEX Options so that any amount owed by the Underlying ETF on the written FLEX Options will be covered by payouts at expiration from the purchased FLEX Options. As a result, the Underlying Funds expect the FLEX Options to be fully covered and no additional collateral will be necessary during the duration of the then current Outcome Period. The Underlying ETF receives premiums in exchange for the written FLEX Options and pays premiums in exchange for the purchased FLEX Options. The OCC and securities exchanges on which the FLEX Options are listed do not charge ongoing fees to writers or purchasers of the FLEX Options during their life for continuing to hold the option contracts but may charge transaction fees. Each of the FLEX Options purchased and sold throughout the Underlying ETFs' respective Outcome Periods will have the same terms, such as strike price and expiration date, as the FLEX Options purchased and sold on the first day of the Outcome Period. On the FLEX Options expiration date, the Underlying ETFs intend to sell the FLEX Options prior to their expiration or cash-settle the FLEX Options and use the resulting proceeds to purchase new FLEX Options for the next Outcome Period.

SPDR^® S&P 500^® ETF Trust ("SPY")

SPY is an exchange-traded unit investment trust that uses a replication strategy, meaning it invests in as many of the stocks in the S&P 500^® Index as is practicable. PDR Services, LLC ("PDR") serves as SPY's sponsor. The investment objective of SPY is to seek to provide investment results that, before fees and expenses, correspond generally to the price and yield performance of the S&P 500^® Index (the "Index"). See below for a description of SPY's principal investment strategies and risks. You can find SPY's prospectus and other information about the ETF, including the statement of additional information and most recent reports to shareholders, online at https://us.spdrs.com/en/etf/spdr-sp-500-etf-SPY. The summary information below regarding SPY comes from its filings with the SEC. You are urged to refer to the SEC filings made by SPY and to other publicly available information (e.g., SPY's annual reports) to obtain an understanding of SPY's business and financial prospects.

The following description of SPY's principal investment strategies was taken directly from SPY's prospectus, dated January 27, 2025 (defined terms have been modified).

"SPY seeks to achieve its investment objective by holding a portfolio of the common stocks that are included in the Index (the "Portfolio"), with the weight of each stock in SPY's Portfolio substantially corresponding to the weight of such stock in the Index. In SPY's prospectus, the term "Portfolio Securities" refers to the common stocks that are actually held by SPY and make up SPY's Portfolio, while the term "Index Securities" refers to the common stocks that are included in the Index, as determined by the index provider, S&P Dow Jones Indices LLC ("S&P"). At any time, SPY's Portfolio will consist of as many of the Index Securities as is practicable. To maintain the correspondence between the composition and weightings of Portfolio Securities and Index Securities, State Street Global Advisors Trust Company (the "Trustee") or its parent company, State Street Bank and Trust Company ("SSBT") adjusts SPY's Portfolio from time to time to conform to periodic changes made by S&P to the identity and/or relative weightings of Index Securities in the Index. SPY's Trustee or SSBT aggregates certain of these adjustments and makes changes to SPY's Portfolio at least monthly, or more frequently in the case of significant changes to the Index. SPY may pay transaction costs, such as brokerage commissions, when it buys and sells securities (or "turns over" its Portfolio). Such transaction costs may be higher if there are significant rebalancings of Index Securities in the Index, which may also result in higher taxes when SPY's units are held in a taxable account. These costs, which are not reflected in SPY's estimated annual Trust ordinary operating expenses, affect SPY's performance. During the most recent fiscal year, SPY's portfolio turnover rate was 2% of the average value of its portfolio. SPY's portfolio turnover rate does not include securities received or delivered from processing creations or redemptions of SPY's units. Portfolio turnover will be a function of changes to the Index as well as requirements of SPY's trust agreement. ... Although SPY may fail to own certain Index Securities at any particular time, SPY generally will be substantially invested in Index Securities, which should result in a close correspondence between the performance of the Index and the performance of SPY. ... SPY does not hold or trade futures or swaps and is not a commodity pool. ... The Index includes five hundred (500) selected companies, all of which are listed on national stock exchanges and spans a broad range of major industries. ... Since 1968, the Index has been a component of the U.S. Commerce Department's list of Leading Indicators that track key sectors of the U.S. economy. Current information regarding the market value of the Index is available from market information services. The Index is determined, comprised and calculated without regard to SPY."

As of October 9, 2025, SPY had significant investments in information technology companies.

Non-Principal Investments

Cash Equivalents and Short-Term Investments

The Fund may invest in securities with maturities of less than one year or cash equivalents, or it may hold cash. The percentage of the Fund invested in such holdings varies and depends on several factors, including market conditions. For temporary defensive purposes and during periods of high cash inflows or outflows, the Fund may invest part or all of its assets in these securities or it may hold cash. During such periods, the Fund may not be able to achieve its investment objective. The Fund may adopt a defensive strategy when the portfolio managers believe securities in which such Fund normally invests have elevated risks due to political or economic factors and in other extraordinary circumstances. For more information on eligible short-term investments, see the SAI.

Illiquid Investments

The Fund may invest up to 15% of its net assets in securities and other instruments that are, at the time of investment, illiquid (determined using the Securities and Exchange Commission's standard applicable to investment companies, i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment). For this purpose, illiquid investments may include, but are not limited to, certain restricted securities (securities the disposition of which is restricted under the federal securities laws), certain securities that may only be resold pursuant to Rule 144A under the Securities Act, and certain repurchase agreements, among others.

Temporary Investments

In response to market, economic, political, or other conditions, the Fund may temporarily invest for defensive purposes that are inconsistent with the Fund's principal investment strategies. If the Fund does so, different factors could affect the Fund's performance, and the Fund may not achieve its investment objective.

Risks of Investing in the Fund

This prospectus describes the risks you may face as an investor in the Fund. It is important to keep in mind that generally, investments with a higher potential reward also have a higher risk of losing money. The reverse is also commonly true: the lower the risk, the lower the potential reward. However, as you consider an investment in the Fund, you should also take into account your tolerance for the daily fluctuations of the financial markets and whether you can afford to leave your money in this investment for a long period of time to ride out down periods.

As with any security, there are market and investment risks associated with your investment in the Fund. The value of your investment will fluctuate over time, and it is possible to lose money. Each risk summarized below is considered a "principal risk" of investing in the Fund, regardless of the order in which it appears.

Principal Risks

Absence of an Active Market Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market makers or authorized participants. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares and market makers are under no obligation to make a market in the Fund's shares. Additionally, only a limited number of institutions act as authorized participants for the Fund and only an authorized participant may engage in creation or redemption transactions directly with the Fund and are not obligated to submit purchase or redemption orders for Creation Units. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund's portfolio securities and the Fund's market price. Any trading halt or other problem relating to the trading activity of these market makers or any issues disrupting the authorized participants' ability to proceed with creation and/or redemption orders could result in a dramatic change in the spread between the Fund's net asset value and the price at which the Fund's shares are trading on the Exchange, which could result in a decrease in value of the Fund's shares. This reduced effectiveness could result in Fund shares trading at a premium or discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem, Fund Shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

Cap Change Risk. A new Underlying ETF cap is established at the beginning of each Target Outcome Period and is dependent on prevailing market conditions. As a result, a cap may rise or fall from one Target Outcome Period to the next and is unlikely to remain the same for consecutive Target Outcome Periods.

Capped Upside Risk. Each Underlying ETF's strategy seeks to provide returns (before fees and expenses) that match the price return of SPY for shares acquired on the first day of a Target Outcome Period and held for the entire Target Outcome Period, subject to a pre-determined upside cap. Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each semi-annual rebalance, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each semi-annual rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period. In the event that the Fund acquires Underlying ETF shares after the first day of a Target Outcome Period and the Underlying ETF has risen in value to a level near or at the cap (because the Fund's potential gain will be limited to the difference between the Underlying ETF's NAV on the date the Fund purchases Underlying ETF shares and the cap), there may be little or no ability for the Fund to experience an investment gain on its shares, however, the Fund will remain vulnerable to downside risks. This could be true for all of the Underlying ETFs held by the Fund at a certain point in time severely limiting the Fund's ability to participate in gains during that time. If SPY experiences gains during a Target Outcome Period, an Underlying ETF will not participate in those gains beyond the cap. If the Fund buys Underlying ETF shares when the price exceeds the cap, the Fund will not experience any gain regardless of the performance of SPY.

Cash Holdings Risk. To the extent the Fund holds cash positions, the Fund risks achieving lower returns and potential lost opportunities to participate in market appreciation which could negatively impact the Fund's performance and ability to achieve its investment objective.

Costs of Buying and Selling Fund Shares. Due to the costs of buying or selling Fund Shares, including brokerage commissions imposed by brokers and bid/ask spreads, frequent trading of Fund Shares may significantly reduce investment results and an investment in Fund Shares may not be advisable for investors who anticipate regularly making small investments.

Counterparty Risk. Underlying ETF transactions involving a counterparty are subject to the risk that the counterparty will not fulfill its obligation to the Underlying ETF. Counterparty risk may arise because of the counterparty's financial condition (i.e., financial difficulties, bankruptcy, or insolvency), market activities and developments, or other reasons, whether foreseen or not. A counterparty's inability to fulfill its obligation may result in significant financial loss to an Underlying ETF and, in turn, the Fund. An Underlying ETF may be unable to recover its investment from the counterparty or may obtain a limited recovery, and/or recovery may be delayed. The OCC acts as guarantor and central counterparty with respect to the FLEX Options. As a result, the ability of an Underlying ETF to meet its objective depends on the OCC being able to meet its obligations. In the unlikely event that the OCC becomes insolvent or is otherwise unable to meet its settlement obligations, an Underlying ETF and, in turn, the Fund could suffer significant losses.

Derivatives Risk. Derivatives are instruments, such as options, futures and forward foreign currency contracts, whose value is derived from that of other assets, rates or indices. The use of derivatives for non-hedging purposes may be considered more speculative than other types of investments. Derivatives can be used for hedging (attempting to reduce risk by offsetting one investment position with another) or non-hedging purposes. Hedging with derivatives may increase expenses, and there is no guarantee that a hedging strategy will work. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. In addition, derivative instruments are subject to counterparty risk, meaning that the party with whom the Fund enters into a derivative transaction may experience a significant credit event and/or may be unwilling or unable to make timely settlement payments or otherwise honor its obligations. Changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index, and the Fund could lose more than the principal amount invested.

Equity Securities Risk. The securities markets are volatile, and the market prices of the SPY's securities may decline generally. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions. If the market prices of the securities owned by the SPY fall, the value of your investment in the Fund will decline.

Flex Options Risk. The Underlying ETFs invest in FLEX Options. Trading FLEX Options involves risks different from, or possibly greater than, the risks associated with investing directly in securities. The Underlying ETFs may experience substantial downside from specific FLEX Option positions and certain FLEX Option positions may expire worthless. The FLEX Options are listed on an exchange; however, no one can guarantee that a liquid secondary trading market will exist for the FLEX Options. In the event that trading in the FLEX Options is limited or absent, the value of the Underlying ETFs' FLEX Options may decrease. In a less

liquid market for the FLEX Options, liquidating the FLEX Options may require the payment of a premium (for written FLEX Options) or acceptance of a discounted price (for purchased FLEX Options) and may take longer to complete. A less liquid trading market may adversely impact the value of the FLEX Options and Underlying ETFs' shares and result in the Underlying ETFs and, in turn, the Fund being unable to achieve their investment objective. Less liquidity in the trading of the Underlying ETF's FLEX Options could have an impact on the prices paid or received by the Underlying ETFs for the FLEX Options in connection with creations and redemptions of the Underlying ETF's shares. Depending on the nature of this impact to pricing, an Underlying ETF may be forced to pay more for redemptions (or receive less for creations) than the price at which it currently values the FLEX Options. Such overpayment or under collection may impact the value of the Underlying ETF and whether the Underlying ETF can satisfy its investment objective. Additionally, in a less liquid market for the FLEX Options, the liquidation of a large number of options may more significantly impact the price. A less liquid trading market may adversely impact the value of the FLEX Options and the value of the Underlying ETFs. The trading in FLEX Options may be less deep and liquid than the market for certain other exchange-traded options, non-customized options or other securities.

Flex Options Valuation Risk. The FLEX Options held by the Underlying ETFs will be exercisable at the strike price only on their expiration date. Prior to the expiration date, the value of the FLEX Options will be determined based upon market quotations or using other recognized pricing methods. The FLEX Options are also subject to correlation risk, meaning the value of the FLEX Options does not increase or decrease at the same rate as SPY (although they generally move in the same direction) or its underlying securities. The value of the FLEX Options prior to the expiration date may vary because of factors other than the value of SPY, such as interest rate changes, changing supply and demand, decreased liquidity of the FLEX Options, 7 a change in the actual and perceived volatility of the stock market and SPY and the remaining time to expiration. FLEX Option prices may also be highly volatile and may fluctuate substantially during a short period of time. During periods of reduced market liquidity or in the absence of readily available market quotations for the holdings of the Underlying ETFs, the ability of the Underlying ETFs to value the FLEX Options becomes more difficult and the judgment of the Underlying ETFs' investment adviser (employing the fair value procedures approved by the Board of Trustees of the Trust) may play a greater role in the valuation of the Underlying ETFs' holdings due to reduced availability of reliable objective pricing data. Consequently, while such determinations may be made in good faith, it may nevertheless be more difficult for the Underlying ETFs to accurately assign a daily value. Under those circumstances, the value of the FLEX Options will require more reliance on the investment adviser's judgment than that required for securities for which there is an active trading market. This creates a risk of mispricing or improper valuation of the FLEX Options which could impact the value paid for shares of the Underlying ETFs.

Fund-of-Funds Risk. Shareholders of the Fund will experience investment returns that are different than the investment returns provided by an Underlying ETF. The Fund does not itself pursue a defined outcome strategy, nor does the Fund itself provide a defined downside against SPY losses. Because the Fund will typically not purchase an Underlying ETF on the first day of a Target Outcome Period, it is not likely that the stated outcome of the Underlying ETF will be realized by the Fund. The Fund will be continuously exposed to the investment profiles of each of the Underlying ETFs during their respective Target Outcome Periods. The Fund, with its aggregate exposure to each of the Underlying ETFs, may have investment returns that are inferior to that of any single Underlying ETF or group of Underlying ETFs over any given time period. In between the semi-annual rebalance period of the Index, because the Fund is not equally weighted on a continuous basis, the Fund may be exposed to one or more Underlying ETFs disproportionately when compared to other Underlying ETFs. In such circumstances, the Fund will be subject to the over-weighted performance of such Underlying ETF. As a shareholder in other ETFs, the Fund bears its proportionate share of each ETF's expenses, subjecting Fund shareholders to duplicative expenses.

Index or Model Constituent Risk. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund's shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund's net asset value could be negatively impacted and the Fund's market price may be below the Fund's net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

Information Technology Companies Risk. SPY invests significantly in information technology companies. Information technology companies produce and provide hardware, software and information technology systems and services. These companies may be adversely affected by rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, the loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards and frequent new product introductions. In addition, information technology companies are particularly vulnerable to federal, state and local government regulation, and competition and consolidation, both domestically and internationally, including competition from foreign competitors with lower production costs. Information technology companies also heavily rely on intellectual property rights and may be adversely affected by the loss or impairment of those rights.

Large Capitalization Companies Risk. SPY invests in the securities of large capitalization companies. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

Management Risk. The Fund is subject to management risk because it is an actively managed portfolio. In managing the Fund's investment portfolio, the portfolio managers will apply investment techniques and risk analyses that may not produce the desired result. There can be no guarantee that the Fund will meet its investment objective.

Market Fluctuation Tax Risk and Cash Transaction Risk. The Fund is acquiring shares of the Underlying ETFs in the open market. When the Fund sells shares of the Underlying ETFs in the open market, the Fund will recognize gain or loss on the disposition of the shares, which could have a negative impact on Fund returns. In addition, note that the Fund may, under certain circumstances, effect a portion of its creations and redemptions for cash rather than in-kind. If the Fund effects redemptions for cash, it may be required to sell shares of the Underlying ETFs in order to obtain the cash needed to distribute redemption proceeds. Any recognized gain on these sales by the Fund will generally cause the Fund to recognize a gain it might not otherwise have recognized, or to recognize such gain sooner than would otherwise be required if it were to distribute such shares only in-kind. The Fund intends to distribute these gains to shareholders to maintain its qualification as a RIC and avoid a fund-level tax. As a result, shareholders may receive a larger amount of, or accelerated, taxable distributions from the Fund than if the Fund did not employ such a strategy. Moreover, cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. These brokerage fees and taxes, which will be higher than if the Fund sold and redeemed its shares entirely in-kind, will be passed on to those purchasing and redeeming Creation Units in the form of creation and redemption transaction fees. In addition, these factors may result in wider spreads between the bid and the offered prices of the Fund's shares than for ETFs that distribute portfolio securities in-kind. The Fund's use of cash for creations and redemptions could also result in dilution to the Fund and increased transaction costs, which could negatively impact the Fund's ability to achieve its investment objective.

Market Risk. The risk that the securities markets will increase or decrease in value is considered market risk and applies to any security. If there is a general decline in the stock or fixed-income market, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests.

New Fund Risk. The Fund is a recently organized investment company with a limited operating history. As a result, prospective investors have a limited track record or history on which to base their investment decision.

Non-Diversification Risk. The Fund is classified as "non-diversified" under the 1940 Act. As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly invested in certain issuers.

or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund's ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

Options Risk. The use of options by the Underlying ETFs involves investment strategies and risks different from those associated with ordinary portfolio securities transactions and depends on the ability of the Underlying ETFs' portfolio managers to forecast market movements correctly. The prices of options are volatile and are influenced by, among other things, actual and anticipated changes in the value of the underlying instrument, or in interest or currency exchange rates, including the anticipated volatility, which in turn are affected by fiscal and monetary policies and by national and international political and economic events. The effective use of options by the Underlying ETFs also depends on the Underlying ETFs' ability to terminate option positions at times deemed desirable to do so. There is no assurance that the Underlying ETFs will be able to effect closing transactions at any particular time or at an acceptable price. In addition, there may at times be an imperfect correlation between the movement in values of options and their underlying securities and there may at times not be a liquid secondary market for certain options.

Premium/Discount Risk. The market price of the Fund's shares will generally fluctuate in accordance with changes in the Fund's net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund's investment advisor cannot predict whether shares will trade below at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund's investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund's shares may become less liquid in response to deteriorating liquidity in the market for the Fund's underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund's shares and their net asset value and the bid/ask spread on the Fund's shares may widen.

Sector Risk. To the extent the SPY invests a significant portion of its assets in a particular sector, a greater portion of the Underlying ETF's and Fund's performance may be affected by the general business and economic conditions affecting that sector. Each sector may share economic risk with the broader market, however there may be economic risks specific to each sector. As a result, returns from those sectors may trail returns from the overall stock market, and it is possible that the SPY may underperform the broader market.

Significant Exposure Risk. The Fund intends to generally rebalance its portfolio to equal weight (i.e., 8.33% per Underlying ETF) semi-annually, in connection with the reset of each Underlying ETF. In between such rebalances, market movements in the prices of the Underlying ETFs may result in the Fund having temporary larger exposures to certain Underlying ETFs compared to others. Under such circumstances, the Fund's returns would be more greatly influenced by the returns of the Underlying ETFs with the larger exposures.

SPY Equity Risk. Because each Underlying ETF holds FLEX Options that reference SPY, each Underlying ETF has exposure to the equity securities markets. Equity securities prices fluctuate for several reasons, including changes in investors' perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

SPY Risk. Each Underlying ETF invests in FLEX Options that reference SPY, which subjects the Underlying ETFs to certain of the risks of owning shares of an ETF as well as the types of instruments in which SPY invests. The value of SPY will fluctuate over

time based on fluctuations in the values of the securities held by SPY, which may be affected by changes in general economic conditions, expectations for future growth and profits, interest rates and the supply and demand for those securities. In addition, ETFs are subject to absence of an active market risk, premium/discount risk and trading issues risk. Brokerage, tax and other expenses may negatively impact the performance of the Underlying ETF and, in turn, the value of the Fund's shares. An ETF that tracks an index may not exactly match the performance of the index due to cash drag, differences between the portfolio of the ETF and the components of the index, expenses and other factors.

Target Outcome Period Risk. Each Underlying ETF's investment strategy is designed to deliver returns that match the price return of SPY if shares are bought on the day on which the Underlying ETF enters into the FLEX Options (i.e., the first day of a Target Outcome Period) and held until those FLEX Options expire at the end of the Target Outcome Period subject to the cap. Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each semi-annual rebalance, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each semi-annual rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period. In the event the Fund acquires shares after the first day of a Target Outcome Period or disposes of shares prior to the expiration of the Target Outcome Period, the value of the Fund's investment in Underlying ETF shares may not be protected against a decline in the value of SPY and may not participate in a gain in the value of SPY for the Fund's investment period.

Tax Risk from Investment in Other Investment Companies. The Fund and each Underlying ETF intend to elect and to qualify each year to be treated as a "regulated investment company" ("RIC") under Subchapter M of the Code. The federal income tax treatment of certain aspects of each Underlying ETF's operations — including its options strategy, its hedging strategy, and the possible application of the "straddle" rules and various loss limitations — is not entirely clear or may be subject to recharacterization by the Internal Revenue Service. It could be more difficult to comply with the tax requirements applicable to RICs if the tax characterization of investments or the tax treatment of the income from such investments were successfully challenged by the Internal Revenue Service. Any such failure to comply with the rules applicable to RICs could cause an Underlying ETF to fail to qualify as such. If an Underlying ETF were to fail to qualify as a RIC for purposes of the Code, the Fund may not meet the diversification tests necessary to qualify as a RIC and thus may lose its own RIC status. If the Fund did not qualify as a RIC for any taxable year and certain relief provisions were not available, the Fund's taxable income would be subject to tax at the Fund level and to a further tax at the shareholder level when such income is distributed. In such event, in order to requalify for taxation as a RIC, the Fund might be required to recognize unrealized gains, pay substantial taxes and interest and make certain distributions. This would cause investors to incur higher tax liabilities than they otherwise would have incurred and would have a negative impact on Fund returns. In such event, the Fund's Board of Trustees may determine to reorganize or close the Fund or materially change the Fund's investment objective and strategies. In the event that the Fund fails to qualify as a RIC, the Fund will promptly notify shareholders of the implications of that failure.

Trading Issues Risk. Trading in Fund Shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in Fund Shares inadvisable. In addition, trading in Fund Shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange's "circuit breaker" rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund's assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

Underlying ETF Concentration Risk. An Underlying ETF may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Underlying ETF's investments more than the market as a whole, to the extent that the Underlying ETF's investments are concentrated in the securities and/or other assets of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector, market segment or asset class.

Underlying ETF Exposure Risk. An investment in the Fund may provide returns that are lower than the returns that an investor could achieve by investing in one or more of the Underlying ETFs alone. Additionally, if one or more of the Underlying ETFs has exceeded its cap at the time that you invest in the Fund, you may derive no benefit from the Fund's investment in that Underlying ETF until the next reset of the Underlying ETF. Likewise, if one or more of the Underlying ETFs has decreased in

value below its downside protection at the time that you invest in the Fund, you may derive no downside protection from the Fund's investment in that Underlying ETF. See Capped Upside Risk above. As a shareholder in other ETFs, the Fund bears its proportionate share of each ETF's expenses, subjecting Fund shareholders to duplicative expenses. The Fund does not itself pursue a target outcome strategy and does not provide any downside protection against Underlying ETF losses.

Underlying ETF Risk. The Fund's investment in shares of the Underlying ETFs subjects it to the risks of owning the securities held by the Underlying the ETF, as well as the same structural risks faced by an investor purchasing shares of the Fund, including absence of an active market risk, premium/discount risk and trading issues risk. As a shareholder in another ETF, the Fund bears its proportionate share of the ETF's expenses, subjecting Fund shareholders to duplicative expenses.

The following are non-principal risks that generally apply to the Fund:

Cybersecurity Risk. Investment companies, such as the Fund, and their service providers are exposed to operational and information security risks resulting from cyberattacks, which may result in financial losses to the Fund and its shareholders. Cyber-attacks include, among other behaviors, stealing or corrupting data maintained online or digitally, denial of service attacks on websites, "ransomware" that renders systems inoperable until ransom is paid, the unauthorized release of confidential information, or various other forms of cybersecurity breaches. Cyber-attacks affecting the Fund, Calamos Advisors, custodian, transfer agent, distributor, market maker, authorized participants, administrator, intermediaries, trading counterparties, and other third-party service providers may adversely impact the Fund or the companies in which the Fund invests, causing the Fund's investments to lose value or to prevent a shareholder redemption or purchase from clearing in a timely manner.

Investment Management Risk. Whether the Fund achieves its investment objective(s) is significantly impacted by whether the Adviser is able to choose suitable investments for the Fund.

Market Disruption Risk. Certain events have a disruptive effect on securities markets, including but not limited to, terrorist attacks, war and other geopolitical events or catastrophes. The Adviser cannot predict the effect of similar events in the future on the U.S. or foreign economies. Certain securities such as high yield and equity securities tend to be impacted more by these events than other types of securities in terms of price and volatility.

Operational Risk. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund's ability to meet its investment objective. Although the Fund and the Adviser seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

Recent Market Events. Since the 2008 financial crisis, financial markets throughout the world have experienced periods of increased volatility, depressed valuations, decreased liquidity and heightened uncertainty and turmoil. This turmoil resulted in unusual and extreme volatility in the equity and debt markets, in the prices of individual securities and in the world economy. Events that have contributed to these market conditions include, but are not limited to, major cybersecurity events, geopolitical events (such as wars (including Russia's military invasion of the Ukraine), terror attacks, natural or environmental disasters, country instability, and public health emergencies), measures to address budget deficits, downgrading of sovereign debt, declines in oil and commodity prices, dramatic changes in currency exchange rates, and public sentiment. In addition, many governments and quasi-governmental entities throughout the world have responded to the turmoil with a variety of significant fiscal and monetary policy changes, including, but not limited to, direct capital infusions into companies, new monetary programs and dramatically lower interest rates.

The full extent of the political, economic and legal consequences of Brexit are not yet fully known, and the long-term impact of Brexit on the UK, the EU and the broader global economy may be significant. As a result of the political divisions within the UK and between the UK and the EU that the referendum vote has highlighted and the uncertain consequences of Brexit, the UK and European economies and the broader global economy could be significantly impacted, potentially resulting in increased market volatility and illiquidity, political, economic, and legal uncertainty, and lower economic growth for companies that rely

significantly on Europe for their business activities and revenues. Any further exits from the EU, or the possibility of such exits, or the abandonment of the Euro, may cause additional market disruption globally and introduce new legal and regulatory uncertainties.

In addition, policy and legislative changes in the United States and in other countries are changing many aspects of financial regulation. The impact of these changes on the markets, and the practical implications for market participants, may not be fully known for some time. Widespread disease and virus epidemics and pandemics, such as the coronavirus outbreak, could likewise be highly disruptive, adversely affecting individual companies, sectors, industries, markets, currencies, interest and inflation rates, credit ratings, investor sentiment, and other factors affecting the value of the Fund's investments.

Portfolio security holdings disclosure

A description of the Fund's policies and procedures in connection with the disclosure of portfolio security holdings of the Fund are available in the SAI and on the Fund's website, www.calamos.com.

Who manages the Fund?

Investment Adviser

The Fund is advised by Calamos Advisors LLC ("Calamos Advisors" or the "Adviser"), 2020 Calamos Court, Naperville, Illinois 60563. Calamos Advisors, an investment adviser registered with the SEC effective May 29, 1987, is a wholly owned subsidiary of Calamos Investments LLC ("CILLC"). CILLC's assets under management as of December 31, 2024, were $40 billion ($38 billion of which represented Calamos Advisors' assets under management). Calamos Asset Management, Inc. ("CAM") is the sole manager of CILLC. As of July 31, 2025, approximately 22.4% of the outstanding interests of CILLC was owned by CAM, 77.72% by Calamos Partners LLC ("CPL"), and 0.04% by Calamos Equity Partners LLC ("CEP"). CAM is owned by John P. Calamos, Sr. and John S. Koudounis. CPL is owned by Calamos Family Partners, Inc. ("CFP") and John S. Koudounis. CFP is beneficially owned by members of the Calamos family, including John P. Calamos, Sr. CEP is owned by John S. Koudounis and Daniel L. Dufresne.

Subject to the overall authority of the Board of Trustees, Calamos Advisors provides continuous investment supervision and management to the Fund under a management agreement and also furnishes office space, equipment and management personnel. For these services, the Fund pays Calamos Advisors a fee based on its average daily net assets, which is accrued daily and paid on a quarterly basis. The Fund will pay fees (before any reimbursement) under the management agreement in the following amounts as a percentage of its average net assets:

ETF				FEES
Calamos Laddered S&P 500^® Structured Alt Protection ETF^®					0.10	%

Out of this management fee, Calamos Advisors pays substantially all expenses of the Fund, including the cost of transfer agency, custody, fund administration, legal, audit and other service and license fees, except for distribution and service fees payable pursuant to a Rule 12b-1 plan, if any, acquired fund fees and expenses, brokerage commissions, and other expenses connected with the execution of portfolio transactions, taxes, interest, and extraordinary expenses.

At a meeting held on June 24, 2025, the board of trustees unanimously approved the renewal of the investment advisory agreement for the Fund. A discussion regarding the basis for the approval by the board of trustees of the agreement is included in the Fund's Form N-CSR for the fiscal year ended July 31, 2025.

Portfolio Managers

David O'Donohue. David O'Donohue joined Calamos Advisors in August 2014 and is a Sr. Co-Portfolio Manager (since February 2024) and Co-Head of Alternative Strategies (since July 2024) and was a Co-Portfolio Manager from September 2015 through January 2024. Between March 2013 and August 2014, he was a Trader at Forty4 Asset Management LLC/Hard8 Futures LLC. Prior thereto, Mr. O'Donohue was a Portfolio Manager at Chicago Fundamental Investment Partners LLC from February 2009 to November 2012.

Jimmy Young. Jimmy Young joined Calamos Advisors in June 2003 and has been a Co-Portfolio Manager since February 2019. Between February 2018 and February 2019, he was an Assistant Portfolio Manager. Prior thereto, he was a senior strategy analyst from September 2015 to February 2018. Between July 2013 and August 2015, he was a strategy analyst.

Eli Pars. Eli Pars joined Calamos Advisors in May 2013 and has been Co-CIO, Co-Head of Alternative Strategies (since July 2024; previously served as Head of Alternative Strategies from September 2015 to June 2024) and Co-Head of Convertible Strategies, as well as a Senior Co-Portfolio Manager since September 2015. Between May 2013 and September 2015, he was a Co-Portfolio Manager. Previously, he was a Portfolio Manager at Chicago Fundamental Investment Partners from February 2009 until November 2012.

Jason Hill. Jason Hill joined Calamos Advisors in March 2004 and has been a Sr. Co-Portfolio Manager since February 2024 and was a Co-Portfolio Manager from June 2014 through January 2024. Between August 2013 and June 2014, he was a Senior Strategy Analyst. Previously, he was a Portfolio Administrator.

Anthony Vecchiolla. Anthony Vecchiolla joined Calamos Advisors in May 2014 and since February 2023 has been a Co-Portfolio Manager. Previously, he was a Research Associate from May 2014 to August 2015, a Research Analyst from September 2015 to February 2020, a Senior Research Analyst from February 2020 to February 2021, and an Assistant Portfolio Manager from February 2021 to January 2023.

Jordan Rosenfeld. Jordan Rosenfeld joined Calamos Advisors in April 2025 and is a Co-Portfolio Manager. Between June 2018 to March 2025, Mr. Rosenfeld was a Senior Director and Portfolio Manager at Milliman, where he was responsible for managing derivatives strategies in exchange-traded funds, mutual funds, and unit investment trusts. Previously, he was a Trader at Gelber Group from January 2016 to December 2017.

The Fund's SAI provides additional information about each portfolio manager, including other accounts they manage, their ownership in the Calamos Family of Funds and their compensation.

Management Approach

Calamos Advisors employs a "team of teams" approach to portfolio management, led by the Global CIO and our CIO team consisting of 5 Co-CIOs with specialized areas of investment expertise. The Global CIO and Co-CIO team are responsible for oversight of investment team resources, investment processes, performance and risk. As heads of investment verticals, Co-CIOs manage investment team members and, along with Co-Portfolio Managers and Associate Portfolio Managers, have day-to-day portfolio oversight and construction responsibilities of their respective investment strategies. While investment research professionals within each Co-CIO's team are assigned specific strategy responsibilities, they also provide support to other investment team verticals, creating deeper insights across a wider range of investment strategies. The combination of specialized investment teams with cross-team collaboration results in what we call our team of teams approach.

This team of teams approach is further reflected in the composition of Calamos Advisors' Investment Committee, made up of the Global CIO, the Co-CIO team, and the Global Head of Trading. Other members of the investment team participate in Investment Committee meetings in connection with specific investment related issues or topics as deemed appropriate.

The structure and composition of the Investment Committee results in a number of benefits, as it:

• Leads to broader perspective on investment decisions: multiple viewpoints and areas of expertise feed into consensus;

• Promotes collaboration between teams; and

• Functions as a think tank with the goal of identifying ways to outperform the market on a risk-adjusted basis.

The objectives of the Investment Committee are to:

• Form the firm's top-down macro view, market direction, asset allocation, and sector/country positioning.

• Establish firm-wide secular and cyclical themes for review.

• Review firm-wide and portfolio risk metrics, recommending changes where appropriate.

• Review firm-wide, portfolio and individual security liquidity constraints.

• Evaluate firm-wide and portfolio investment performance.

• Evaluate firm-wide and portfolio hedging policies and execution.

• Evaluate enhancements to the overall investment process.

How to Buy and Sell Shares

Fund Shares are listed for secondary trading on the Exchange under the symbol CPSL and individual Fund Shares may only be purchased and sold in the secondary market through a broker-dealer. The Exchange and secondary markets are closed on weekends and also are generally closed on the following holidays: New Year's Day, Dr. Martin Luther King, Jr. Day, Presidents' Day, Good Friday, Memorial Day (observed), Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The Exchange may close early on the business day before certain holidays and on the day after Thanksgiving Day. Exchange holiday schedules are subject to change without notice. If you buy or sell Fund Shares in the secondary market, you will pay the secondary market price for Fund Shares. In addition, you may incur customary brokerage

commissions and charges and may pay some or all of the spread between the bid and the offered price in the secondary market on each leg of a round trip (purchase and sale) transaction.

The trading prices of Fund Shares will fluctuate continuously throughout trading hours based on market supply and demand rather than the relevant Fund's net asset value, which is calculated at the end of each business day.

Fund Shares will trade on the Exchange at prices that may be above (i.e., at a premium) or below (i.e., at a discount), to varying degrees, the daily net asset value of Fund Shares. The trading prices of Fund Shares may deviate significantly from the Fund's net asset value during periods of market volatility. Given, however, that Fund Shares can be issued and redeemed daily in Creation Units, the Adviser believes that large discounts and premiums to net asset value should not be sustained over long periods.

Authorized Participants may acquire shares directly from the Fund, and Authorized Participants may tender their shares for redemption directly to the Fund, at NAV per share only in Creation Units. Purchases and redemptions directly with the Fund must follow the Fund's procedures, which are described in the SAI.

The Fund may liquidate and terminate at any time without shareholder approval.

Book Entry

Fund Shares are held in book-entry form, which means that no stock certificates are issued. The Depository Trust Company ("DTC") or its nominee is the record owner of all outstanding Shares of the Fund and is recognized as the owner of all Shares for all purposes.

Investors owning Fund Shares are beneficial owners as shown on the records of DTC or its participants. DTC serves as the securities depository for all Fund Shares. Participants in DTC include securities brokers and dealers, banks, trust companies, clearing corporations and other institutions that directly or indirectly maintain a custodial relationship with DTC. As a beneficial owner of Fund Shares, you are not entitled to receive physical delivery of stock certificates or to have Fund Shares registered in your name, and you are not considered a registered owner of Fund Shares. Therefore, to exercise any right as an owner of Fund Shares, you must rely upon the procedures of DTC and its participants. These procedures are the same as those that apply to any other securities that you hold in book entry or "street name" form.

Fund Share Trading Prices

The trading prices of Shares of the Fund on the Exchange may differ from the Fund's daily NAV. Market forces of supply and demand, economic conditions and other factors may affect the trading prices of Shares of the Fund.

The approximate value of Shares of the Fund, an amount representing on a per share basis the sum of the current market price of the cash or securities, as applicable, accepted by the Fund in exchange for Shares of the Fund and an estimated cash component, if any, is disseminated every 15 seconds throughout the trading day through the facilities of the Consolidated Tape Association. This approximate value should not be viewed as a "real-time" update of the NAV per Share of the Fund because the approximate value may not be calculated in the same manner as the NAV, which is computed once a day, generally at the end of the business day. The Fund is not involved in, or responsible for, the calculation or dissemination of the approximate value of the Fund Shares and the Fund does not make any warranty as to its accuracy.

Frequent Purchases and Redemptions of Fund Shares

Shares of the Fund may be purchased and redeemed directly from the Fund only in Creation Units by Authorized Participants. The vast majority of trading in Shares of the Fund occurs on the secondary market, and does not involve the Fund directly. In-kind purchases and redemptions of Creation Units by Authorized Participants and cash trades on the secondary market are unlikely to cause many of the harmful effects of frequent purchases and/or redemptions of Fund Shares. Cash purchases and/or redemptions of Creation Units, however, can result in disruption of portfolio management, dilution to the Fund and increased transaction costs, which could negatively impact the Fund's ability to achieve its investment objective, and may lead to the realization of capital gains. These consequences may increase as the frequency of cash purchases and redemptions of Creation Units by Authorized Participants increases. However, direct trading by Authorized Participants is critical to ensuring that Fund Shares trade at or close to NAV.

The Fund impose no restrictions on the frequency of purchases and redemptions ("market timing"). To minimize these potential consequences of frequent purchases and redemptions of Fund Shares, the Fund employs fair valuation pricing, and imposes transaction fees on purchases and redemptions of Creation Units to cover the custodial and other costs the Fund incurs in effecting trades. In addition, the Adviser monitors trades by Authorized Participants for patterns of abusive trading and the Fund reserves the right to not accept orders from Authorized Participants that the Adviser has determined may be disruptive to the management of the Fund, or otherwise are not in the best interests of the Fund. For these reasons, the Board has not adopted policies and procedures with respect to frequent purchases and redemptions of Fund Shares. The Trust's policies and procedures regarding frequent purchases and redemptions may be modified by the Board of Trustees at any time.

The Trust's policies and procedures prohibit the practice of any officer or employee of the Trust, a Trust investment adviser (including any sub-adviser), the distributor, custodian, or transfer agent, or other affiliated person of the Trust placing orders to purchase or redeem shares of a series of the Trust after the designated time as of which the Fund calculates its NAV (i.e., "late trading").

Distribution and Service Plan

The Fund has adopted a distribution and service plan ("Plan") pursuant to Rule 12b-1 under the 1940 Act. Under the Plan, the Fund is authorized to pay distribution fees to the Distributor and other firms that provide distribution and shareholder services ("Service Providers"). If a Service Provider provides such services, the Fund may pay fees at an annual rate not to exceed 0.25% of average daily net assets, pursuant to Rule 12b-1 under the 1940 Act.

No distribution or service fees are currently paid by the Fund, however, and there are no current plans to impose these fees. In the event Rule 12b-1 fees are charged, over time they would increase the cost of an investment in the Fund because they would be paid on an ongoing basis.

Fund Website and Disclosure of Portfolio Holdings

The Trust maintains a website for the Fund at www.calamos.com. Among other things, this website includes this Prospectus and the SAI, and will include the Fund's holdings, the Fund's last annual and semi-annual reports (when available), pricing information about Fund Shares trading on the Exchange, daily NAV calculations and a historical comparison of the trading prices to NAV.

Each day the Fund is open for business, the Trust publicly disseminates the Fund's full portfolio holdings as of the close of the previous day through its website at www.calamos.com. A description of the Trust's policies and procedures with respect to the disclosure of the Fund's portfolio holdings is available in the Fund's SAI.

Dividends, Other Distributions and Taxes

Fund Distributions

The Fund intends to distribute its net realized capital gains, if any, to shareholders annually. Ordinarily, the Fund intends to declare and pay dividends from net investment income, if any, at least annually.

Distributions in cash may be reinvested automatically in additional whole Fund Shares only if the broker through whom you purchased Fund Shares makes such option available. The Fund realizes capital gains or losses whenever it sells securities. Net long-term capital gains are distributed to shareholders as "capital gain dividends."

Brokers may make available to their customers who own Fund Shares the DTC book-entry dividend reinvestment service. To determine whether the dividend reinvestment service is available and whether there is a commission or other charge for using this service, consult your broker. Brokers may require Fund shareholders to adhere to specific procedures and timetables. If this service is available and used, dividend distributions of both income and net realized gains will be automatically reinvested in additional whole Fund Shares of the Fund purchased in the secondary market. Without this service, investors would receive their distributions in cash.

Taxes

As with any investment, you should consider how your investment in Fund Shares of the Fund will be taxed. The tax information in this prospectus is provided only as general information. This section is current as of the date of this prospectus.

Tax laws and interpretations change frequently, and these summaries do not describe all of the tax consequences to all taxpayers. For example, these summaries generally do not describe your situation if you are a corporation, a non-U.S. person, a broker-dealer, or other investor with special circumstances. However, with respect to certain tax issues, the summaries describe the general tax treatment of certain distributions made to corporations and non-U.S. persons. In addition, this section does not describe your state, local or non-U.S. tax consequences. You should consult your own tax advisor about the tax consequences of an investment in Fund Shares.

Fund distributions to you and the sale or redemption of your Fund Shares will have tax consequences to you. Such consequences may be different if you hold your Fund Shares through a tax-exempt entity or tax-advantaged retirement account, such as an individual retirement account or 401(k) plan.

The Fund intends to elect to be treated and to qualify each year as a regulated investment company (a "RIC") under the Internal Revenue Code of 1986, as amended (the "Code"). As a RIC, the Fund is generally not subject to corporate-level U.S. federal income tax on any net ordinary income or capital gains that are timely distributed to shareholders. Each Underlying Fund also intends to qualify each year as a RIC. The tax treatment of certain investments made by the Underlying ETFs is not certain. An adverse determination or future guidance by the IRS might affect an Underlying ETF's ability to qualify as a RIC, and such a failure by an Underlying ETF may bear adversely on the Fund's ability to qualify for treatment as a RIC.

The Fund's failure to qualify as a RIC or to meet minimum distribution requirements would result (if certain relief provisions were not available) in corporate-level taxation and, consequently, a reduction in amounts available for distribution to shareholders.

Taxes on Distributions

Distributions by the Fund generally are taxable to you as ordinary income or capital gains. Distributions are subject to federal income tax, whether received in cash or reinvested in additional Fund shares or shares of another fund, and may be subject to state or local taxes. Distributions of the Fund's "investment company taxable income" generally will be taxable as ordinary income to the extent of the Fund's current or accumulated earnings and profits. Notwithstanding the foregoing, distributions that are attributable to "qualified dividends" received by the Fund may be eligible to be taxed at long-term capital gains rates, as long as the Fund and the shareholder meet certain holding period requirements. It is not anticipated that the Fund will have qualified dividend income.

Distributions of the Fund's net capital gain that are properly reported by the Fund as "capital gain dividends" will generally be taxable to you as long-term capital gains, currently at a maximum rate of 20%, regardless of your holding period in the Fund's Shares. Distributions in excess of the Fund's current and accumulated earnings and profits first will reduce your adjusted tax basis in your Fund Shares and, after the adjusted basis is reduced to zero, will constitute capital gain. Such capital gain will be long-term capital gain and thus, will be taxed at a maximum rate of 20%, if the distributions are attributable to Fund Shares that you have held for more than one year.

Certain non-corporate taxpayers will also be subject to a 3.8% U.S. federal Medicare contribution tax with respect to the lesser of (1) their "net investment income" or (2) the excess of their "modified adjusted gross income" over a threshold amount ($200,000 for single taxpayers and $250,000 for taxpayers who are married and filing jointly).

Corporate shareholders of the Fund are generally eligible for a dividends-received deduction with respect to ordinary income dividends (but not capital gain dividends) properly designated as eligible for such deduction by the Fund, as long as the Fund and the corporate shareholder meet certain holding period and other requirements. It is not anticipated that the Fund will make distributions eligible for the dividend-received deduction.

Under a dividend reinvestment service, you may have the option to have all cash distributions automatically reinvested in additional Fund Shares. Any distributions reinvested under such a service will nevertheless be taxable to you as described above.

You will have an adjusted basis in the additional Fund Shares purchased through such a reinvestment service equal to the amount of the reinvested distribution plus the amount of any fees charged for the transaction. The additional Fund Shares will have a holding period commencing on the day following the day on which they are credited to your account.

A distribution will reduce the Fund's NAV per Share and generally will be taxable to you as ordinary income or capital gain even if it is paid from income or gains earned by the Fund before you invested in the Fund. From an investment standpoint, such a distribution constitutes a return of capital. However, from a tax standpoint, it constitutes taxable income. In general, distributions are subject to federal income tax as of the date of payment. However, distributions paid in January will be treated as paid on December 31 of the prior year if they were declared and payable to shareholders of record on a date in October, November or December of the prior year.

The Fund intends to invest substantially all of its assets in the Underlying ETFs, and so substantially all of the Fund's income will be as a result of distributions from Underlying ETFs and the sale of shares of the Underlying ETFs. An Underlying ETF's transactions in derivatives, including FLEX Options, may be subject to one or more special tax rules. These rules may affect whether gains and losses recognized by an Underlying ETF are treated as ordinary or capital, accelerate the recognition of income or gains to the Underlying ETF, defer losses to the Underlying ETF, and cause adjustments in the holding periods of the Underlying ETF's securities, thereby affecting whether capital gains and losses are treated as short-term or long-term. These rules could therefore affect the amount, timing and/or character of distributions by the Underlying ETFs to the Fund and thus distributions by the Fund to shareholders.

You may be subject to federal back-up withholding tax, if you do not provide the Fund with a taxpayer identification number (for an individual, a social security number) and make other required certifications, or the Internal Revenue Service informs the Fund that your tax identification number is incorrect. Backup withholding is not an additional tax. You may claim the amount withheld as a credit on your federal income tax return, provided you furnish the appropriate information to the Internal Revenue Service.

Taxes When Shares are Sold

Any capital gain or loss realized upon a sale of Fund Shares is generally treated as long-term capital gain or loss if you have held the Fund Shares for more than one year and as short-term capital gain or loss if you have held the Fund Shares for one year or less. The ability to deduct capital losses realized on a sale of Fund Shares may be limited.

Taxes on Purchase and Redemption of Creation Units

An Authorized Participant that exchanges equity securities for Creation Units will generally recognize a gain or a loss on the exchange. Any such gain or loss will be equal to the difference between the market value of the Creation Units at the time of the exchange, plus (or minus) the cash amount received (or paid), and such Authorized Participant's aggregate basis in the securities surrendered. A person who redeems Creation Units for equity securities will generally recognize a gain or loss equal to the difference between the aggregate market value of the securities received plus (or minus) any cash received (or paid), and such person's basis in the Creation Units redeemed. The Internal Revenue Service, however, may assert that a loss realized upon an exchange of securities for Creation Units cannot be deducted currently under the rules governing "wash sales," or on the basis that there has been no significant change in the Authorized Participant's economic position with respect to such Creation Units. Persons exchanging securities should consult their own tax advisor with respect to the applicability of the wash sale rules and the availability and timing of a deduction for any loss. In addition, when a regulated investment company redeems a shareholder in kind, the regulated investment company generally is not required to recognize taxable gains in respect of the portfolio securities it distributes to the redeeming shareholder. However, the Fund may be required to recognize taxable gain on the distribution of certain securities, and the Internal Revenue Service may assert that the Fund must recognize taxable gain in respect of certain other securities that the Fund distributes to a shareholder in exchange for Creation Units, which may increase the amount of taxable gains that the Fund would otherwise be required to distribute in order to maintain its qualification as a regulated investment company and avoid the Fund-level tax. In addition, the Fund may, under certain circumstances, effect a portion of its creations and redemptions for cash rather than in-kind, in which case the Fund may be required to sell shares of the Underlying ETFs in order to obtain the cash needed to distribute redemption proceeds which may increase the amount of taxable gains that the Fund would otherwise be required to distribute.

Any capital gain or loss realized upon a redemption of Creation Units is generally treated as long-term capital gain or loss if the Creation Units have been held for more than one year and as short-term capital gain or loss if the Creation Units have been

held for one year or less. If you purchase or redeem Creation Units, you will be sent a confirmation statement showing how many Fund Shares you purchased or sold and at what price.

Authorized Participants that are dealers may be subject to special tax rules and should consult their own tax advisors regarding the tax consequences of purchasing and redeeming Creation Units in their capacity as dealers.

Treatment of Fund Expenses

Expenses incurred and deducted by the Fund will generally not be treated as income taxable to you.

Non-U.S. Investors

If you are a non-U.S. investor (i.e., an investor other than a U.S. citizen or resident or a U.S. corporation, partnership, estate or trust), you should be aware that, generally, subject to applicable tax treaties, distributions from the Fund will be characterized as dividends for U.S. federal income tax purposes (other than dividends which the Fund properly reports as capital gain dividends) and will be subject to U.S. federal income taxes, including withholding taxes, subject to certain exceptions described below. However, distributions received by a non-U.S. investor from the Fund that are properly reported by the Fund as capital gain dividends may not be subject to U.S. federal income taxes, including withholding taxes, provided that the Fund makes certain elections and certain other conditions are met.

Distributions may be subject to a U.S. withholding tax of 30% in the case of distributions to (i) certain non-U.S. financial institutions that have not entered into an agreement with the U.S. Treasury to collect and disclose certain information and are not resident in a jurisdiction that has entered into such an agreement with the U.S. Treasury and (ii) certain other non-U.S. entities that do not provide certain certifications and information about the entity's U.S. owners. The Internal Revenue Service and the Department of Treasury have issued proposed regulations providing that these withholding rules will not be applicable to the gross proceeds of share redemptions or capital gains dividends that the Fund pays.

Other Tax Matters

The foregoing is only a summary of certain federal income tax considerations of investing in the Fund under current law, which is subject to change in the future. Shareholders who are not U.S. persons within the meaning of the Code, such as non-resident aliens, foreign trusts or estates, or foreign corporations or partnerships may be subject to different U.S. federal income tax treatment.

You may also be subject to state and local taxes on distributions paid by the Fund, and sales and redemptions of Fund shares. You should consult your tax advisor for further information regarding federal, state, local and/or foreign tax consequences relevant to your specific tax situation. More information about taxes can be found in the Fund's SAI.

Net Asset Value

The NAV of shares is determined at the close of regular trading on the New York Stock Exchange (normally 4:00 p.m. Eastern Time) on each day the New York Stock Exchange ("NYSE") is open. NAV is computed by determining the aggregate market value of all assets of the Fund, less its liabilities, divided by the total number of shares outstanding ((assets-liabilities)/number of shares = NAV). The NYSE is closed on weekends and New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The NAV takes into account the expenses and fees of the Fund, including management, administration, and distribution fees, which are accrued daily. The determination of NAV for the Fund for a particular day is applicable to all applications for the purchase of shares, as well as all requests for the redemption of shares, received by the Fund (or an authorized broker or agent, or its authorized designee) before the close of trading on the NYSE on that day.

Generally, securities traded or dealt in upon one or more securities exchanges (whether domestic or foreign) for which market quotations are readily available and not subject to restrictions against resale shall be valued at the last quoted sales price on the primary exchange or, in the absence of a sale on the primary exchange, at the mean between the current bid and ask prices on such exchange. Securities primarily traded in the National Association of Securities Dealers' Automated Quotation System ("NASDAQ") National Market System for which market quotations are readily available shall be valued using the NASDAQ official closing price. Securities that are not traded or dealt in any securities exchange (whether domestic or foreign) and for which over-the-counter market quotations are readily available generally shall be valued at the last sale price or, in the absence

of a sale, at the mean between the current bid and ask price on such over-the-counter market. Debt securities not traded on an exchange may be valued at prices supplied by a pricing agent (s) based on broker or dealer supplied valuations or matrix pricing, a method of valuing securities by reference to the value of other securities with similar characteristics, such as rating, interest rate and maturity. Futures, swaps and options contracts listed for trading on a futures or options exchange or board of trade for which market quotations are generally available are valued at the last quoted sale price, or, in the absence of a sale, at the mean of the last bid and ask price. Total return swaps on exchange-listed securities are valued at the last quoted sale price, or, in the absence of a sale, at the mean of the last bid and ask price.

Securities held by the Fund are valued in accordance with policies and procedures established by the Adviser pursuant to Rule 2a-5 under the 1940 Act and approved by and subject to the oversight of the Board of Trustees ("Valuation Procedures"). If market quotations are not readily available, securities or other assets will be valued at their fair value as determined in good faith by the Adviser in accordance with procedures approved by the Board and evaluated by the Board as to the reliability of the fair value method used. In these cases, the Fund's NAV will reflect certain portfolio securities' fair values rather than their market prices. Fair value pricing involves subjective judgments, and it is possible that the fair value determined for a security or other asset may be materially different than the value that could be realized upon the sale of that security or other asset. The fair value prices can differ from market prices. The Board of Trustees has designated Calamos Advisors as "valuation designee" for the Fund. The valuation designee is responsible for determining the value of the Fund's investments. The designee may also enlist third party consultants such as an audit firm or financial officer of a security issuer on an as-needed basis to assist in determining a security-specific fair value. The Board reviews and ratifies the execution of this process and the resultant fair value prices at least quarterly to ensure the process produces reliable results.

The Fund may use independent pricing services to assist in calculating the value of the Fund's securities or other assets.

With respect to any portion of the Fund's assets that are invested in one or more open-end management investment companies registered under the 1940 Act, the Fund's net asset value is calculated based upon the net asset values of those open-end management investment companies, and the prospectuses for these companies explain the circumstances under which those companies will use fair value pricing and the effects of using fair value pricing.

Fund Service Providers

State Street Bank and Trust Company ("State Street"), located at One Congress Street, Suite 1, Boston, Massachusetts 02114-2016, serves as the Fund's administrator, custodian, fund accounting and transfer agent.

Calamos Financial Services LLC ("CFS") serves as the distributor of Creation Units for the Fund on an agency basis. The Distributor does not maintain a secondary market in Fund Shares.

Ropes & Gray LLP, located at 191 North Wacker Drive, 32^nd Floor, Chicago, IL 60606, serves as legal counsel to the Trust.

Premium/Discount Information

Information showing the number of days the market price of the Fund Shares was greater (at a premium) and less (at a discount) than the Fund's NAV for the most recently completed calendar year, and the most recently completed calendar quarters since that year (or the life of the Fund, if shorter), is available at www.calamos.com.

Investments in Other Investment Companies

Generally, investments in ETFs are subject to statutory limitations prescribed by the 1940 Act. These limitations include a prohibition on the Fund acquiring more than 3% of the voting shares of any other investment company, a prohibition on investing more than 5% of the Fund's total assets in the securities of any one investment company or more than 10% of its total assets, in the aggregate, in investment company securities.

The Fund will invest in the Underlying ETFs beyond these statutory limitations in reliance on Section 12(d)(1)(G) of the 1940 Act.

FINANCIAL HIGHLIGHTS

Selected data for a share outstanding throughout the year was as follows:

	September 9, 2024• through July 31,
	2025
Per share operating performance
Net asset value, beginning of year	$	24.92
Income from investment operations:
Net investment income (loss)(a)		(0.02	)
Net realized and unrealized gain (loss)		1.57
Total from investment operations		1.55
Less distributions to common shareholders from:
Net investment income		—
Total distributions		—
Net asset value, end of year	$	26.47
Total return applicable to common shareholders
Total investment return based on:
Net asset value(b)		6.22	%
Ratios to average net assets applicable to common shareholders
Net expenses		0.10	%(c)(d)
Net investment income (loss)		(0.07	%)(c)(d)

Supplemental data

Net assets applicable to common shareholders, end of year (000)				$	79,401
Portfolio turnover rate(e)(f)					18	%

• Commencement of operations.

(a) Net investment income (loss) allocated based on average shares method.

(b) Total return measures net investment income and capital gain or loss from portfolio investments assuming reinvestment of dividends and capital gains distributions. Total return is not annualized for periods that are less than a full year and does not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.

(d) The Fund invests in other funds and indirectly bears its proportionate share of fees and expenses incurred by the underlying funds in which the Fund is invested. This ratio does not include these indirect fees and expenses.

(e) Not annualized.

(f) Portfolio turnover rate excludes securities received or delivered from in-kind processing of creations or redemptions.

Continuous Offering

The method by which Creation Units of Fund Shares are created and traded may raise certain issues under applicable securities laws. Because new Creation Units of Fund Shares are issued and sold by the Fund on an ongoing basis, a "distribution," as such term is used in the Securities Act of 1933, as amended (the "Securities Act"), may occur at any point. Broker-dealers and other persons are cautioned that some activities on their part may, depending on the circumstances, result in their being deemed participants in a distribution in a manner which could render them statutory underwriters and subject them to the prospectus delivery requirements and liability provisions of the Securities Act. For example, a broker-dealer firm or its client may be deemed a statutory underwriter if it takes Creation Units after placing an order with the Distributor, breaks them down into constituent Fund Shares and sells the Fund Shares directly to customers or if it chooses to couple the creation of a supply of new Fund Shares with an active selling effort involving solicitation of secondary market demand for Fund Shares. A determination of whether one is an underwriter for purposes of the Securities Act must take into account all the facts and circumstances pertaining to the activities of the broker-dealer or its client in the particular case, and the examples mentioned above should not be considered a complete description of all the activities that could lead to a characterization as an underwriter.

Broker-dealer firms should also note that dealers who are not "underwriters" but are effecting transactions in Fund Shares, whether or not participating in the distribution of Fund Shares, are generally required to deliver a prospectus. This is because the prospectus delivery exemption in Section 4(3) of the Securities Act is not available in respect of such transactions as a result of Section 24(d) of the 1940 Act. As a result, broker-dealer firms should note that dealers who are not "underwriters" but are participating in a distribution (as contrasted with engaging in ordinary secondary market transactions) and thus dealing with the Fund Shares that are part of an overallotment within the meaning of Section 4(3)(C) of the Securities Act, will be unable to take advantage of the prospectus delivery exemption provided by Section 4(3) of the Securities Act. For delivery of prospectuses to exchange members, the prospectus delivery mechanism of Rule 153 under the Securities Act is only available with respect to transactions on a national exchange.

Disclaimer

The "S&P 500^®" is a product of S&P Dow Jones Indices LLC or its affiliates ("SPDJI") and has been licensed for use by Calamos Advisors LLC ("Calamos Advisors"). S&P^®, S&P 500^®, SPX^®, SPY^®, US 500^TM, The 500^TM, iBoxx^®, iTraxx^® and CDX^® are trademarks of S&P Global, Inc. or its affiliates ("S&P"); Dow Jones^® is a registered trademark of Dow Jones Trademark Holdings LLC ("Dow Jones"). It is not possible to invest directly in an index. The Fund is not sponsored or sold by SPDJI, Dow Jones, S&P, any of their respective affiliates (collectively, "S&P Dow Jones Indices"). S&P Dow Jones Indices do not make any representation or warranty, express or implied, to the owners of the Fund or any member of the public regarding the advisability of investing in securities generally or in the Fund particularly or the ability of the S&P 500^® Index to track general market performance. Past performance of an index is not an indication or guarantee of future results. S&P Dow Jones Indices' only relationship to Calamos Advisors with respect to the S&P 500^® Index is the licensing of the Index and certain trademarks, service marks and/or trade names of S&P Dow Jones Indices and/or its licensors. The S&P 500^® Index is determined, composed and calculated by S&P Dow Jones Indices without regard to Calamos Advisors or the Fund. S&P Dow Jones Indices have no obligation to take the needs of Calamos Advisors or the owners of the Fund into consideration in determining, composing or calculating the S&P 500^® Index. S&P Dow Jones Indices have no obligation or liability in connection with the administration, marketing or trading of the Fund. There is no assurance that investment products based on the S&P 500^® Index will accurately track index performance or provide positive investment returns. S&P Dow Jones Indices LLC is not an investment adviser, commodity trading advisor, commodity pool operator, broker dealer, fiduciary, promoter" (as defined in the Investment Company Act of 1940, as amended), "expert" as enumerated within 15 U.S.C. § 77k (a) or tax advisor. Inclusion of a security, commodity, crypto currency or other asset within an index is not a recommendation by S&P Dow Jones Indices to buy, sell, or hold such security, commodity, crypto currency or other asset, nor is it considered to be investment advice or commodity trading advice.

NEITHER S&P DOW JONES INDICES NOR THIRD PARTY LICENSOR GUARANTEES THE ADEQUACY, ACCURACY, TIMELINESS AND/OR THE COMPLETENESS OF THE S&P 500^® INDEX OR ANY DATA RELATED THERETO OR ANY COMMUNICATION, INCLUDING BUT NOT LIMITED TO, ORAL OR WRITTEN COMMUNICATION (INCLUDING ELECTRONIC COMMUNICATIONS) WITH RESPECT THERETO. S&P DOW JONES INDICES SHALL NOT BE SUBJECT TO ANY DAMAGES OR LIABILITY FOR ANY

ERRORS, OMISSIONS, OR DELAYS THEREIN. S&P DOW JONES INDICES MAKES NO EXPRESS OR IMPLIED WARRANTIES, AND EXPRESSLY DISCLAIMS ALL WARRANTIES, OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR USE OR AS TO RESULTS TO BE OBTAINED BY CALAMOS ADVISORS, OWNERS OF THE FUNDS, OR ANY OTHER PERSON OR ENTITY FROM THE USE OF THE S&P 500^® INDEX OR WITH RESPECT TO ANY DATA RELATED THERETO. WITHOUT LIMITING ANY OF THE FOREGOING, IN NO EVENT WHATSOEVER SHALL S&P DOW JONES INDICES BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO, LOSS OF PROFITS, TRADING LOSSES, LOST TIME OR GOODWILL, EVEN IF THEY HAVE BEEN ADVISED OF THE POSSIBLITY OF SUCH DAMAGES, WHETHER IN CONTRACT, TORT, STRICT LIABILITY, OR OTHERWISE. S&P DOW JONES INDICES HAS NOT REVIEWED, PREPARED AND/OR CERTIFIED ANY PORTION OF, NOR DOES S&P DOW JONES INDICES HAVE ANY CONTROL OVER, THE LICENSEE PRODUCT REGISTRATION STATEMENT, PROSPECTUS OR OTHER OFFERING MATERIALS. THERE ARE NO THIRD-PARTY BENEFICIARIES OF ANY AGREEMENTS OR ARRANGEMENTS BETWEEN S&P DOW JONES INDICES AND CALAMOS ADVISORS, OTHER THAN THE LICENSORS OF S&P DOW JONES INDICES.

Summary of Certain Provisions of the Second Amended and Restated Trust Instrument

The summary below is a synopsis of certain provisions contained in the Trust's Second Amended and Restated Trust Instrument (the "Trust Instrument"). Shareholders should refer to the Trust Instrument for further information. Defined terms have the meanings contained in the Trust Instrument.

Derivative Actions

The Second Amended and Restated Trust Instrument (the "Trust Instrument") requires, within Section 9 of Article IV, that before bringing any derivative action on behalf of the Fund, Shareholders must have made a written demand to the Board of Trustees requesting that they cause the Trust or affected Series or Class, as applicable, to file the action itself.

In order to warrant consideration, any such written demand must include at least the following:

(1) a detailed description of the action or failure to act complained of and the facts upon which each such allegation is made;

(2) a statement to the effect that the complaining Shareholders believe that they will fairly and adequately represent the interests of similarly situated Shareholders in enforcing the right of the Trust or the affected Series or Class, as applicable and an explanation of why the complaining Shareholders believe that to be the case;

(3) a certification that the following requirements have been met, as well as information reasonably designed to allow the Trustees to verify that certification:

(a) each complaining Shareholder was a Shareholder of the Trust or the affected Series or Class, as applicable, at the time of the action or failure to act complained of, or acquired the Shares afterwards by operation of law from a Person who was a Shareholder at that time; and

(b) each complaining Shareholder was a Shareholder of the Trust or the affected Series or Class, as applicable, as of the time the demand required by Section 9 of Article IV was made; and

(4) a certification that each complaining Shareholder will be a Shareholder of the Trust or the affected Series or Class, as applicable as of the commencement of the derivative action.

The Trust Instrument further provides that at least 10% of the Shareholders of the Trust or the affected Series or Class, as applicable, must join in bringing the derivative action. This provision does not apply to claims brought under the federal securities laws.

The Trust Instrument also provides that a copy of the derivative complaint must be served on the Trust, assuming the requirements described above have already been met and the derivative action has not been barred as further described in the Trust Instrument.

Forum and Waiver of Jury Trial

Section 10 of Article X of the Trust Instrument outlines which shareholder actions must be brought in state court and which must be brought in federal court. This section states in particular that, unless the Trust consents in writing to the selection of an alternative forum, the Federal District Courts of the United States of America shall be the sole and exclusive forum for the

For more detailed information on the Fund, several additional sources of information are available to you. The Fund's SAI, incorporated by reference into this prospectus, contains detailed information on the Fund's policies and operation. Additional information about the Fund's investments is available in the annual and semi-annual reports to shareholders and in Form N-CSR. In the Fund's annual reports, you will find a discussion of the market conditions and investment strategies that significantly impacted the Fund's performance during the last fiscal year. In Form N-CSR, you will find the Fund's annual and semi-annual financial statements. The Fund's most recent SAI, annual or semi-annual reports and certain other information are available free of charge by calling the Fund at (866) 363-9219, on the Fund's website at www.calamos.com or through your financial advisor. Shareholders may call the toll-free number above with any inquiries.

You may obtain this and other information regarding the Fund, including the SAI and Codes of Ethics adopted by the Adviser, Distributor and the Trust, directly from the SEC. Information on the SEC's website is free of charge. Visit the SEC's on-line EDGAR database at http://www.sec.gov. You may also request information regarding the Fund by sending a request (along with a duplication fee) to the SEC by sending an electronic request to [email protected].

Fund Name				Ticker				Exchange
Calamos Laddered S&P 500^® Structured Alt Protection ETF^®				CPSL				Cboe BZX Exchange, Inc.

Calamos Laddered S&P 500^® Structured Alt Protection ETF^®					1
Other Important Information Regarding Fund Shares					11
Additional Information About Investment Strategies and Related Risks					12
Fund Facts					26
Who Manages the Fund?					26
How to Buy and Sell Shares					27
Dividends, Other Distributions and Taxes					29
Net Asset Value					32
Fund Service Providers					33
Premium/Discount Information					33
Investments by Other Investment Companies					33
Financial Highlights					34
Other Information					35