Preliminary Prospectus

Dated January 28, 2026

Subject to Completion

The information in this preliminary prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and is not soliciting an offer to buy these securities in any state where the offer is not permitted.

Fund Name		Ticker				Exchange
Calamos [Tax-Aware Collateral] ETF

Prospectus _______________, 2026

The fund listed above (the "Fund") is a series of the Calamos ETF Trust (the "Trust") and an exchange-traded fund ("ETF"). The Fund lists and principally trades its shares on the __________ ("_________" or the "Exchange").

Market prices may differ to some degree from the net asset value of the shares. Unlike mutual funds, the Fund issues and redeems shares at net asset value, only in large blocks of shares called "Creation Units."

Except when aggregated in Creation Units, the shares are not redeemable securities of the Fund.

The U.S. Securities and Exchange Commission ("SEC") has not approved or disapproved these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

Calamos [Tax-Aware Collateral] ETF			5
Other Important Information Regarding Fund Shares			12
Additional Information About Investment Strategies and Related Risks			13
Fund Facts			21
Who Manages the Fund?			21
How to Buy and Sell Shares			22
Dividends, Other Distributions and Taxes			24
Net Asset Value			26
Fund Service Providers			27
Premium/Discount Information			27
Investments by Other Investment Companies			27
Financial Highlights			28
Other Information			28

Calamos [Tax-Aware Collateral] ETF

Investment Objective

Calamos [Tax-Aware Collateral] ETF (the "Fund") is to seek capital appreciation by investing in FLEX options box spreads.

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 (ongoing expenses that you pay each year as a percentage of the value of your investments):

Management Fees		%
Distribution and/or Service Fees (12b-1)	0.00	%
Other Expenses¹	0.00	%
Total Annual Fund Operating Expenses		%

1 "Other Expenses" is an estimate based on the expenses the Fund expects to incur for the current fiscal year.

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:

Year 1				Year 3
$				$

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. Because the Fund has not yet commenced operations, portfolio turnover information is unavailable at this time.

Principal Investment Strategies

The Fund is an actively managed exchange-traded fund (“ETF”) that seeks to achieve its investment objective through multiple combinations of synthetic long and short exchange-listed options positions, collectively referred to herein as a Box Spread (“Box Spread”).

Box Spreads. A Box Spread is an offsetting set of options, which may include Flexible Exchange Options ("FLEX Options"). Box Spreads consist of a synthetic long position (where the Fund owns or purchases a synthetic position in the underlying) coupled with an offsetting synthetic short position (where the Fund owes or sells a synthetic position in the underlying) through a combination of options contracts on a reference asset at the same expiration date. The reference asset in the context of the Fund’s Box Spreads will be the S&P 500 ETF (“SPY”) (the “Underlying ETF”). The Fund may structure its Box Spread using a four-options-contracts approach, a three-options-contracts approach, or a two-options-contracts approach.

Under a four-options-contracts approach, the synthetic long position consists of (i) buying a call option and (ii) selling a put option, each on the same reference asset and each with the same strike price and expiration date. The synthetic short position consists of (i) buying a put option and (ii) selling a call option, each on the same reference asset and each with the same expiration date as the synthetic long but with a different strike price from the synthetic long position.

The Fund may also utilize a three-options-contract approach where three FLEX Options positions comprise the Box Spread. These positions consist of a long call option, a short call option, and a long put option.

In instances where the call and put options that the Fund may purchase are substantially in-the-money and the synthetic long and short positions comprising the Box Spread can effectively be constructed without writing call or put options, the Fund may elect to use a two-options-contract approach where it will not write call or put options and will instead utilize a long call and a long put.

The Adviser to the Fund will determine the use of either a four option contracts, three option contracts, or two option contracts approach as it deems necessary and desirable to facilitate trading, pricing and/or valuation in order to best effectuate the Fund’s investment objectives.

The difference between the strike prices of the synthetic long position and the synthetic short position determines the expiration value (or value at maturity) of the Box Spread. An important feature of the Box Spread construction process is that it seeks to eliminate market risk tied to price movements associated with the underlying options' reference asset. Once the Box Spread is initiated, its return from the initiation date through expiration will not change due to price movements in the underlying options' reference assets.

Under the four-options-contracts Box Spread structure (as described above), the Fund’s synthetic long position is created though the purchase of a call option and sale of a put option, where the call option and put option are each purchased or sold on the same reference asset, strike price and expiration date. The Fund’s synthetic short position is created through the purchase of a put option and sale of a call option, where the call option and put option are each purchased or sold on the same reference asset with the same expiration date as the synthetic long position, but the synthetic short position is at a higher strike price from the synthetic long position. The synthetic long and short options positions, in combination, are designed to offset one another, creating a market-neutral position with a fixed payoff at expiration of the options contracts. The Fund’s strategy of replicating the ownership of long and short positions at two different prices effectively creates a “box” that locks in a fixed payout, regardless of the underlying asset’s movement.

The Fund’s expected profit from a Box Spread transaction is expected to equal approximately the difference between the price paid for the Box Spread and its expiration value minus any transaction costs associated with the options trades. The effective yield on each Box Spread is determined by annualizing the profit over the price paid.

Box Spread Portfolio.

The options contracts that the Fund utilizes in implementing its investment strategy will be FLexible EXchange options (“FLEX Options”) on the SPDR S&P 500 ETF (“SPY”)(the “Underlying ETF”). The Fund will only invest in options contracts that are listed for trading on regulated U.S. exchanges. FLEX Options are a type of exchange-listed options contract with uniquely customizable terms that allow investors to customize key terms like type, strike price and expiration date that are standardized in a typical options contract. FLEX Options are also guaranteed for settlement by the OCC.

The Fund will be primarily invested in Box Spreads and cash, targeting a Box Spread market value in line with the Fund’s total net assets. The Box Spreads are constructed using two FLEX Options positions (long call, long put), three FLEX Options positions (long call, short call, long put) and/or four FLEX Options positions (long call, short call, long put, short put) at two different strike prices with the same maturity.

The Fund will utilize “European Style” option contracts, which are only exercisable on the expiration date of the contract, as opposed to “American Style” options that can be exercised at any time prior to expiration. In holding synthetic positions created by the Box Spread that remain intact until maturity, the Fund seeks to prevent any part of the strategy from being closed out early due to early exercise of one or more of the option contracts so that the Fund can reliably capture the intended payoff—the difference between the strike prices—without the risk of unexpected changes or disruptions before the expiration date.

The Fund may hold collateral, such as cash, cash equivalents or securities issued or guaranteed by the U.S. government, that may be used to pay costs related to implementing the Fund’s investment strategy.

Box Spread Portfolio Ladder Approach.

The Fund expects, under normal conditions, to invest substantially all of its total assets in one or multiple Box Spreads at any given time, with each Box Spread utilizing FLEX Options on the Underlying ETF and having maturities typically ranging from 1 to 6 months. The Fund may employ a laddered approach investing in Box Spreads with staggered maturities to provide liquidity and scale while seeking to maximize yield capture.

The returns on the Fund’s Box Spread investments will depend on a number of factors, including changes in market prices of new options contracts when modifying its portfolio holdings and expected interest rates and the Fund’s trading activity, among other things. As a result, returns may vary. Further, given that the Fund may hold multiple Box Spreads at a time, there is no fixed return for a given period, and the value of the Fund can increase or decrease based on the different factors discussed above.

The Fund will typically sell or “roll” any Box Spread at any time prior to maturity. When selling or rolling a Box Spread, the Fund may incur additional transaction costs than if it waited until such Box Spread expired. The Fund may engage in active and frequent trading of portfolio securities to achieve its investment objective.

The Fund will not concentrate (i.e., invest more than 25% of its total assets) its investments in securities of issuers in any industry or group of industries, except to the extent that the Underlying ETF invests more than 25% of its assets in an industry or group of industries. This restriction does not apply to securities issued or guaranteed by the U.S. Government, its agencies or instrumentalities, or securities of other investment companies.

The Fund is classified as “non-diversified” under the Investment Company Act of 1940 (the “1940 Act”).

General Information about FLEX Options

FLEX Options are customizable exchange-traded option contracts guaranteed for settlement by the Options Clearing Corporation (the "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 Fund will hold and that reference the SPDR S&P 500 ETF ("SPY") will give the Fund 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 SPY's value and a strike price, depending on whether the option is a put or call option and whether the Fund purchases or sells the option. The Fund will purchase call options (giving the Fund the right to receive shares of SPY or a cash payment) and put options (giving the Fund the right to deliver shares of SPY or a cash payment), and may sell (i.e., write) call options (giving the Fund the obligation to deliver shares of SPY or a cash payment) and put options (giving the Fund the obligation to receive shares of SPY or a cash payment) in instances where it is deemed necessary or desirable to construct the Box Spread. In instances where the purchased call and put options are substantially in-the-money and the synthetic long and short positions comprising the Box Spread can effectively be constructed without writing call or put options, the Fund may elect not to write call or put options. The Fund intends to use FLEX Options in constructing Box Spreads. The Fund 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.

The Underlying ETF

The Underlying ETF 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 the Underlying ETF's sponsor. The investment objective of the Underlying ETF 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 the Underlying ETF's principal investment strategies and risks. You can find the Underlying ETF's prospectus and other information about the ETF, including the statement of additional information and most recent reports to shareholders, online at https://www.ssga.com/us/en/intermediary/etfs/spdr-sp-500-etf-trust-spy.

The summary information below regarding the Underlying ETF comes from its filings with the SEC. You are urged to refer to the SEC filings made by the Underlying ETF and to other publicly available information (e.g., the Underlying ETF's annual reports) to obtain an understanding of the ETF's business and financial prospects. The following description of the Underlying ETF's principal investment strategies was taken directly from the Underlying ETF's prospectus, dated January 27, 2025 ("SPY" refers to the Underlying ETF; other defined terms have been modified).

SPY seeks to provide investment results that, before expenses, correspond generally to the price and yield performance of the S&P 500^® Index (the “Index”). 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 3% 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 November 11, 2025, the Underlying ETF 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:

● 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.

● Box Spread Risk — If one or more of the individual option positions that comprise a Box Spread are modified or closed separately prior to the option contract's expiration, then the Box Spread may no longer effectively eliminate risk tied to underlying reference asset's price movement. Furthermore, the Box Spread's value is derived in the market and is in part based on the time until the options comprising the Box Spread expire and the prevailing market interest rates. The Fund's ability to utilize Box Spreads effectively is dependent on the availability and willingness of other market participants to sell the FLEX option contracts that comprise the Box Spreads to the Fund at competitive prices. If the Box Spread does not perform as intended, the Fund could have exposure to the underlying reference asset of the options comprising the Box Spread, which is expected to be the SPY. In such a scenario, the Fund would be subject to the risks of 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.

● 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.

● Clearing Member Default Risk — Transactions in some types of derivatives, including the options held by the Fund, are required to be centrally cleared (“cleared derivatives”). In a transaction involving cleared derivatives, the Fund’s counterparty is a clearinghouse, such as the OCC, rather than a bank or broker. Since the Fund is not a member of clearinghouses, and only members of a clearinghouse (“clearing members”) can participate directly in the clearinghouse, the Fund will hold cleared derivatives through accounts at clearing members. With regard its cleared derivatives positions, the Fund will make payments (including margin payments) to, and receive payments from, a clearinghouse through their accounts at clearing members. Customer funds held at a clearing organization in connection with any option contracts are held in a commingled omnibus account and are not identified to the name of the clearing member’s individual customers. As a result, assets deposited by the Fund with any clearing member as margin for its options position may, in certain circumstances, be used to satisfy losses of other clients of the Fund’s clearing member. In addition, although clearing members guarantee performance of their clients’ obligations to the clearinghouse, there is a risk that the assets of the Fund might not be fully protected in the event of the clearing member’s bankruptcy. The Fund is also subject to the risk that a limited number of clearing members are willing to transact on the Fund’s behalf, which heightens the risks associated with a clearing member’s default. If a clearing member defaults, the Fund could lose some or all of the benefits of a transaction entered into by the Fund with the clearing member. The loss of a clearing member for the Fund to transact with could result in increased transaction costs and other operational issues that could impede the Fund’s ability to implement its investment strategy. If the Fund cannot find a clearing member to transact with on the Fund’s behalf, the Fund may be unable to effectively implement its investment strategy.

● Correlation Risk — The FLEX Options held by the Fund 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, consistent with the Fund's valuation policy. The FLEX option's value will be affected by, among other things, changes in interest rates. The value of the Fund's FLEX Options positions is not anticipated to increase or decrease at the same rate as the Underlying ETF's share price, and it is possible they may move in different directions, and as a result, the Fund's NAV may not increase or decrease at the same rate as the Underlying ETF's share price.

● 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.

● Credit Risk — The Fund's collateral investments may be subject to credit risk, which is the risk that an issuer or counterparty will fail to pay principal or interest when due.

● Derivatives Risk — Derivatives are instruments, such as swaps, options, futures and forward foreign currency contracts, whose value is derived from that of other assets, rates or indices. Derivatives can be used for hedging (attempting to reduce risk by offsetting one investment position with another) or non-hedging purposes. The use of derivatives for non-hedging purposes may be considered more speculative than other types of investments. The use of derivatives will increase expenses and volatility, and there is no guarantee that a derivatives strategy will work as anticipated. . The Fund will not use derivatives for non-hedging purposes. Further, 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. The Fund's exposure to the underlying reference asset subjects it to risks associated with equity markets. The value of the underlying reference asset may fluctuate, sometimes rapidly and unpredictably, due to factors affecting the U.S. equity markets generally or particular segments of the market. If the market prices of the securities to which the underlying reference asset is exposed decline, the value of your investment in the Fund will decline.

● FLEX Options Risk — Trading FLEX Options involves risks different from, and possibly greater than, the risks associated with investing directly in securities or in other types of options. FLEX Options, like other listed options, are traded on the U.S. options markets and are issued by OCC. However, unlike other options, the terms of FLEX Options are not all standardized. When a FLEX Option is purchased and sold in an opening transaction, the parties to the transaction have the flexibility, within limitations set forth in the rules of the options market on which the transaction occurs, to fix certain of the option's terms. The flexibility to fix certain terms is what makes FLEX Options different from other types of options. Because many of the terms of FLEX Options are not standardized, it is less likely that there will be an active secondary market in which holders and writers of such options will be able to close out their positions by offsetting sales and purchases. Because FLEX Options have variable terms that are fixed by the parties, there are no pre-established series of FLEX Options. Rather, any different series of FLEX Options may be created and outstanding at any given time as a result of the various designations of variable terms that are made in different transactions. Secondary trading interest in FLEX Options may therefore be spread over a larger number of series than the trading interest in other options, the trading interest in any particular series of FLEX Options may be very limited, the secondary markets in FLEX Options may be less deep, liquid and continuous than the markets in other options on the same underlying interests, and the premiums for FLEX Options may not correlate with premiums for such other options. In the event that trading in the FLEX Options is limited or absent, the value of the Fund's 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 Fund Shares and result in the Fund being unable to achieve its investment objective. Less liquidity in the trading of the Fund's FLEX Options could have an impact on the prices paid or received by the Fund for the FLEX Options in connection with creations and redemptions of the Fund Shares. Depending on the nature of this impact to pricing, the Fund 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 Fund and whether the Fund 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 your investment. 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. The Fund also is subject to the risk that the OCC will become insolvent or otherwise be unable to meet its obligations, which could cause the Fund to suffer losses which may be significant.

● Interest Rate Risk — The value of the Fund's fixed-income investments may be affected by changes in interest rates. When interest rates rise, the value of fixed-income investments generally falls.

● Liquidity Risk — Liquidity risk exists when particular investments are difficult to purchase or sell. The Fund's investments in illiquid securities may reduce the returns of the Fund because it may be unable to sell the illiquid securities at an advantageous time or price.

● Market Maker Risk — If the Fund has lower average daily trading volumes, it may rely on a small number of third-party market makers to provide a market for the purchase and sale of Fund Shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund's net asset value and the price at which the Fund Shares are trading on the Exchange, which could result in a decrease in value of the Fund Shares. In addition, 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. This reduced effectiveness could result in Fund Shares trading at a discount to net asset value and also in greater than normal intra-day bid-ask spreads for Fund Shares.

● Market Risk — The risk that the securities markets will increase or decrease in value is considered market risk and applies to any security, including those held by the Index Portfolio. While the Box Spread strategy is meant to mitigate this risk, the strategy provides this protection only during the term of the box spread and only for the underlying reference asset. The value of securities upon renewal of a given Box Spread may differ due to changes in the market price of the contracts and of the underlying reference asset that occurred while the prior Box Spread was in place.

● 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 Code. In addition, this makes the Fund more susceptible to risks associated with a single economic, political, or regulatory occurrence.

● Options Risk — The Fund's ability to close out its position as a purchaser or seller of an exchange-listed put or call option is dependent, in part, upon the liquidity of the options market. There are significant differences between the securities and options markets that could result in an imperfect correlation among these markets, causing a given transaction not to achieve its objectives. The Fund's ability to utilize options successfully will depend on the ability of the Fund's investment adviser to predict pertinent market movements, which cannot be assured.

If the Fund were unable to close out an option that it had purchased on a security, it would have to exercise the option to realize any profit or the option would expire and become worthless. If the Fund were unable to close out a covered call option that it had written on a security, it would not be able to sell the underlying security until the option expired. As the writer of a covered call option on a security, the Fund foregoes, during the option's life, the opportunity to profit from increases in the market value of the security covering the call option above the sum of the premium and the exercise price of the call. The hours of trading for listed options may not coincide with the hours during which the underlying financial instruments are traded. To the extent that the option markets close before the markets for the underlying financial instruments, significant price and rate movements can take place in the underlying markets that cannot be reflected in the option markets until the next trading day.

● Premium/Discount Risk — Fund Shares may trade above or below their NAV. The market prices of Fund Shares will generally fluctuate in accordance with changes in NAV as well as the relative supply of, and demand for, Fund Shares on the Exchange. The trading price of Fund Shares may deviate significantly from NAV during periods of market volatility.

● Secondary Market Trading Risk — Investors buying or selling Fund Shares in the secondary market will pay brokerage commissions or other charges imposed by brokers as determined by that broker. Brokerage commissions are often a fixed amount and may be a significant proportional cost for investors seeking to buy or sell relatively small amounts of Fund Shares. Although the Fund Shares are listed on the Exchange, there can be no assurance that an active or liquid trading market for them will develop or be maintained. The Fund's shares may trade at prices substantially different from NAV during periods of market stress or when the complex underlying derivatives are difficult to value. In addition, trading in Fund Shares on the Exchange may be halted.

● Sector Risk — To the extent the Underlying ETF invests a significant portion of its assets in a particular sector, a greater portion of the 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 Underlying ETF may underperform the broader market.

● Tax Risk — The Fund intends to elect and to qualify each year to be treated as a regulated investment company ("RIC") under Subchapter M of the Internal Revenue Code of 1986, as amended (the "Code"). The federal income tax treatment of the securities in which the Fund may invest, including the Fund's option strategy, may not be 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 the Fund to fail to qualify as such.

The U.S. federal income tax treatment of a derivative may not be as favorable as a direct investment in the underlying asset and may adversely affect the timing, character, and amount of income the Fund realizes from its investments. In addition, certain derivatives are subject to mark-to-market, constructive sale, straddle and conversion transaction provisions of the Code. If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable distributions that will need to be made by the Fund.

Code Section 1258 requires that certain capital gain from an investment be recharacterized as ordinary income if substantially all of the expected return is attributable to the time value of holding the investment and such investment falls into certain defined categories (a “conversion transaction”). If any of the Fund’s transactions or holding of Shares are deemed to be conversion transactions, certain gains from such transactions or Shares would be treated as ordinary income, which could result respectively in the Fund having not distributed enough income to qualify as a RIC (with the same tax consequences described above) or gain on the disposition of Shares being treated as ordinary income. No assurance can be given that the IRS or a court will not treat any such transactions by the Fund or the holding of Shares as conversion transactions.

● 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 shares inadvisable. Further, 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.

● Underlying ETF Risk — The Fund invests in FLEX Options that reference an ETF, which subjects the Fund to certain of the risks of owning shares of an ETF as well as the types of instruments in which the Underlying ETF invests. The value of an ETF will fluctuate over time based on fluctuations in the values of the securities held by the ETF, 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, correlation 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.

● Valuation Risk — During periods of reduced market liquidity or in the absence of readily available market quotations for the holdings of the Fund, the ability of the Fund to value the FLEX Options may become more difficult. In market environments where there is reduced availability of reliable objective pricing data, the judgment of Calamos Advisors in determining the fair value of the security may play a greater role. While such determinations may be made in good faith, it may nevertheless be more difficult for the Fund to accurately assign a daily value.

Fund Performance

As of the date of this prospectus, the Fund has not yet commenced operations and therefore does not have a performance history. Once available, performance information is available at no cost by visiting the Fund's website at “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
Shaheen Iqubal	Since ______, 2026	SVP, Co-Portfolio Manager
Jordan Rosenfeld	Since ______, 2026	VP, Co-Portfolio Manager

Other Important Information Regarding Fund Shares

Portfolio Holdings. The Fund's portfolio holdings will be 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 the 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 make distributions monthly and distribute long-term 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), the 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.

Additional Information About Investment Strategies and Related Risks

The Fund's investment objective and each of the policies described herein are non-fundamental policies that may be changed by the Board of Trustees of the Trust (the "Board") without shareholder approval. The Fund may liquidate and terminate at any time without shareholder approval.

What are the investment objectives and principal strategies for the Fund?

Principal Investment Strategies

Overview

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. Each of the policies described herein, including the investment objective of the Fund, constitutes a non-fundamental policy that may be changed by the Board of Trustees of the Trust (the “Board”) without shareholder approval. Certain fundamental policies of the Fund are set forth in the Fund’s Statement of Additional Information (the “SAI”). There can be no assurance that the Fund’s objective will be achieved.

The Fund’s investments are subject to certain requirements imposed by law and regulation, as well as the Fund’s investment strategy. These requirements are generally applied at the time the Fund invests its assets. If, subsequent to an investment by the Fund, this requirement is no longer met, the Fund’s future investments will be made in a manner that will bring the Fund into compliance with this requirement.

Additional Information About the Fund’s Principal Investment Strategy

Box Spread Portfolio.

Box Spread Portfolio Ladder Approach.

The Fund is classified as “non-diversified” under the Investment Company Act of 1940 (the “1940 Act”).

General Information about FLEX Options

FLEX Options are customizable exchange-traded option contracts guaranteed for settlement by the Options Clearing Corporation (the "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 Fund will hold and that reference the SPDR S&P 500 ETF ("SPY") will give the Fund 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 SPY's value and a strike price, depending on whether the option is a put or call option and whether the Fund purchases or sells the option. The Fund will purchase call options (giving the Fund the right to receive shares of SPY or a cash payment) and put options (giving the Fund the right to deliver shares of SPY or a cash payment), and may sell (i.e., write) call options (giving the Fund the obligation to deliver shares of SPY or a cash payment) and put options (giving the Fund the obligation to receive shares of SPY or a cash payment) in instances where it is deemed necessary or desirable to construct the Box Spread. In instances where the purchased call and put options are substantially in-the-money and the synthetic long and short positions comprising the Box Spread can effectively be constructed without writing call or put options, the Fund may elect not to write call or put options. The Fund intends to use FLEX Options in constructing Box Spreads. The Fund 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.

The Underlying ETF

SPY seeks to provide investment results that, before expenses, correspond generally to the price and yield performance of the S&P 500^® Index (the “Index”). 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 3% 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 November 11, 2025, the Underlying ETF had significant investments in information technology companies.

Principal Risks

● Credit Risk — The Fund's collateral investments may be subject to credit risk, which is the risk that an issuer or counterparty will fail to pay principal or interest when due.

● Derivatives Risk — Derivatives are instruments, such as swaps, options, futures and forward foreign currency contracts, whose value is derived from that of other assets, rates or indices. Derivatives can be used for hedging (attempting to reduce risk by offsetting one investment position with another) or non-hedging purposes. The use of derivatives for non-hedging purposes may be considered more speculative than other types of investments. The use of derivatives will increase expenses and volatility, and there is no guarantee that a derivatives strategy will work as anticipated. The Fund will not use derivatives for non-hedging purposes. Further, 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.

● Options Risk. There are significant differences between the securities and options markets that could result in an imperfect correlation among these markets, causing a given transaction not to achieve its objectives. The Fund's ability to utilize options successfully will depend on Calamos Advisors' ability to predict pertinent market movements, which cannot be assured.

The Fund's ability to close out its position as a purchaser or seller of an Options Clearing Corporation or exchange-listed put or call option is dependent, in part, upon the liquidity of the options market. If the Fund were unable to close out an option that it had purchased on a security, it would have to exercise the option to realize any profit or the option would expire and become worthless. If the Fund were unable to close out a covered call option that it had written on a security, it would not be able to sell the underlying security until the option expired. As the writer of a covered call option on a security, the Fund foregoes, during the option's life, the opportunity to profit from increases in the market value of the security covering the call option above the sum of the premium and the exercise price of the call. The hours of trading for listed options may not coincide with the hours during which the underlying financial instruments are traded. To the extent that the option markets close before the markets for the underlying financial instruments, significant price and rate movements can take place in the underlying markets that cannot be reflected in the option markets until the next trading day.

● Sector Risk — To the extent the Underlying ETF invests a significant portion of its assets in a particular sector, a greater portion of the 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 Underlying ETF may underperform the broader market.

● Tax Risk — – The Fund intends to elect and to qualify each year to be treated as a regulated investment company ("RIC") under Subchapter M of the Internal Revenue Code of 1986, as amended (the "Code"). The federal income tax treatment of the securities in which the Fund may invest, including the Fund's option strategy, may not be 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 the Fund to fail to qualify as such.

The Fund may enter into various transactions, including transactions involving options contracts, for which there is a lack of clear guidance under the Internal Revenue Code of 1986, as amended (the “Code”), which may affect the taxation of the Fund. The U.S. federal income tax treatment of a derivative may not be as favorable as a direct investment in the underlying asset and may adversely affect the timing, character, and amount of income the Fund realizes from its investments. The use of certain derivatives may cause the Fund to realize higher amounts of ordinary income or short-term capital gain, to suspend or eliminate holding periods of positions, and/or to defer realized losses, potentially increasing the need to make taxable distributions, including those that will be taxed at the rates applicable to ordinary income. For example, exchange-traded options on certain indexes are currently taxed under Code Section 1256 pursuant to which profit and loss with respect to such options are subject to tax as 60% long-term and 40% short-term capital gain or loss regardless of the Fund’s holding period. In addition, certain derivatives are subject to mark-to-market, constructive sale, and straddle and conversion transaction provisions of the Code. If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable distributions that will need to be made by the Fund.

The Fund intends to qualify as a RIC under the Code, which requires the Fund to distribute a certain portion of its income and gains each year, among other requirements. Similar to other ETFs, when the Fund disposes of appreciated property by distributing such appreciated property in-kind pursuant to redemption requests of its shareholders under Code Section 852(b)(6), the Fund does not recognize any built-in gain in such appreciated property. If the Internal Revenue Service (“IRS”) or a court disagrees with the Fund’s position as to the applicability of this nonrecognition rule to the Fund’s dispositions, the Fund may not have distributed sufficient income or gains to qualify as a RIC. If, in any year, the Fund fails to qualify as a RIC, the Fund itself generally would be subject to regular corporate U.S. federal income tax, and distributions received by its shareholders would be subject to further U.S. federal income tax. Alternatively, the Fund may be required to pay a deficiency dividend (without having received additional cash) and applicable interest, and such dividend would be paid to the then current shareholders of the Fund. Failure to comply with the requirements for qualification as a RIC would have significant negative economic consequences to the Fund’s shareholders.

In addition, the U.S. federal income tax treatment of a derivative may not be as favorable as a direct investment in the underlying asset and may adversely affect the timing, character, and amount of income the Fund realizes from its investments. Code Section 1258 requires that certain capital gain from an investment be recharacterized as ordinary income if substantially all of the expected return is attributable to the time value of holding the investment and such investment falls into certain defined categories (a “conversion transaction”). If any of the Fund’s transactions or holding of Shares are deemed to be conversion transactions, certain gains from such transactions or Shares would be treated as ordinary income, which could result respectively in the Fund having not distributed enough income to qualify as a RIC (with the same tax consequences described above) or gain on the disposition of Shares being treated as ordinary income. No assurance can be given that the IRS or a court will not treat any such transactions by the Fund or the holding of Shares as conversion transactions.

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

Market Events Risk. Economies and financial markets throughout the world are increasingly interconnected. Economic, financial or geopolitical events, trading and tariff arrangements (including trade or diplomatic disputes resulting in the imposition of economic sanctions or the threat of new or modified sanctions), terrorism, wars, cybersecurity events, natural or environmental disasters and other circumstances in one country or region could have profound impacts on global economies or markets. Widespread disease and virus epidemics, 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 Portfolio's investments. As a result, whether or not the Portfolio invests in securities of issuers located in or with significant exposure to the countries directly affected, the value and liquidity of the Portfolio's investments may be negatively affected.

Policy and legislative changes in the United States and in other countries may impact the financial markets. The impact of these changes on the markets, and the practical implications for market participants, may not be fully known for some time.

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 crises, 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, terror attacks, natural or environmental disasters, country instability, and public health emergencies), measures to address budget deficits, downgrading of sovereign debt, dramatic changes in currency exchange rates, and public sentiment.

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. Economic, financial or political events, trading and tariff arrangements, terrorism, natural disasters, rapid technological developments, such as artificial intelligence, and other circumstances in one country or region could have profound impacts on global economies or markets. Widespread disease and virus epidemics, 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.

Fund Facts

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 [Tax-Aware Collateral] ETF				%

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 [ ], the Board of Trustees approved the Investment Management Agreement for the Fund. A discussion regarding the basis for the Board's approval of the Investment Management Agreement on behalf of the Fund will be included in the first shareholder report that covers the period in which the Fund commences operations.

Portfolio Managers

Shaheen Iqubal. Shaheen Iqubal joined Calamos Advisors in 2017 as Senior Vice President, Head of Quantitative Investments, Co-Head of Risk. In February 2025, he was named Co-Portfolio Manager, and prior to that from January 2024 through January 2025 served as Associate Portfolio Manager. Shaheen is responsible for oversight of our quantitative investment and risk management teams. Prior to joining the firm, Shaheen was executive director and senior quantitative analyst in the applied research group at UBS Asset Management.

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 CAIE 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 imposes 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 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 make distributions monthly and distribute long-term capital gains, 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 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 intends to qualify each year, as a regulated investment company (a "RIC") under 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. However, 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.

For purposes of the diversification tests, the identification of the issuer (or, in some cases, issuers) of a particular investment can depend on the terms and conditions of such investment. In particular, there is no published IRS guidance or case law on how to determine the "issuer" of various derivatives that the Fund may enter into. Therefore, there is a risk that the Fund will not meet the Code's diversification requirements and will not qualify, or will be disqualified, as a RIC.

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 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 unrealized appreciation or 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's transactions in derivatives (including the options described above), as well as any of its hedging, short sale, securities loan or similar transactions may be subject to one or more special tax rules. These rules may affect whether gains and losses recognized by the Fund are treated as ordinary or capital, accelerate the recognition of income or gains to the Fund, defer losses to the Fund, and cause adjustments in the holding periods of the Fund'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 to shareholders and thus taxes payable by 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 IRS 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 IRS.

Taxes When Fund 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. Long-term capital gain is taxed to individuals at reduced rates relative to short-term capital gain 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 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 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 IRS, 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 IRS 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.

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 in the SAI.

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 IRS and the Department of the 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"), located at 2020 Calamos Court, Naperville, Illinois 60563, serves as the principal underwriter for the following investment companies registered under the Investment Company Act of 1940, as amended: Calamos Investment Trust, Calamos Advisors Trust, Calamos Antetokounmpo Sustainable Equities Trust, Calamos ETF Trust, and Calamos Aksia Alternative Credit and Income Fund. CFS is the proposed principal underwriter for the new series of Calamos ETF Trust, where it would serve as 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 by Other Investment Companies

Section 12(d)(1) of the 1940 Act restricts investments by investment companies in the securities of other investment companies, including Fund Shares. The SEC adopted Rule 12d1-4 under the 1940 Act on November 19, 2020, which became effective January 19, 2021. The Fund is required to comply with the conditions of Rule 12d1-4, which allows, subject to certain conditions, the Fund to invest in other registered investment companies and other registered investment companies to invest in the Fund beyond the limits contained in Section 12(d)(1) of the 1940 Act.

Financial Highlights

The Fund has not yet commenced operations and therefore has no performance history as of the date of this prospectus. Financial information is therefore not yet available.

Other Information

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.

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 resolution of any complaint asserting a cause of action arising under any federal securities law. This provision may increase costs for a shareholder to bring a claim or may limit a shareholder's ability to bring a claim in a judicial forum that they find more convenient or favorable. While the enforceability of the exclusive forum provisions may be challenged, this section also provides that if any provisions of Section 10 shall be held to be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining portions will still apply.

Section 10 of Article X of the Trust Instrument also states that shareholders and all other such persons bringing any such suit, action, or proceeding in the Superior Court in the State of Delaware waive the right to a trial by jury to the fullest extent permitted by law.

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. 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 period. 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].

Calamos [Tax-Aware Collateral] ETF

2020 Calamos Court
Naperville, IL 60563-2787
866.363.9219

www.calamos.com

SEC File
#811-22887
CAIESTAPRO [____2026]