Summary Prospectus by Investment Company (Form 497K)

April 13, 2026

Summary Prospectus

Calamos Tax-Aware Collateral ETF

(BZX - CBOX)

Before you invest, you may want to review the Fund's prospectus and statement of additional information, which contain more information about the Fund and its risks. You can find the Fund's prospectus, statement of additional information, reports to shareholders and other information about the Fund online at www.calamos.com/resources. You can also get this information at no cost by calling 866.363.9219 or by sending an e-mail request to [email protected]. The current prospectus and statement of additional information dated April 13, 2026, and the independent registered public accounting firm's report and financial statements included in the Fund's Form N-CSR, dated July 31, 2025, are incorporated by reference into this summary prospectus.

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):

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

2 Calamos Advisors has entered into expense limitation agreement with the Trust pursuant to which Calamos Advisors has agreed to reimburse the Fund 0.05% of the average net assets of the Fund such that the unitary fee is reduced from 0.19% to 0.14%. The agreement extends to December 1, 2029.

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:

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.

Calamos Tax-Aware Collateral ETF

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.

The Fund will invest the underlying portfolio in Box-Spreads which, in turn, may meet the requirements to qualify for more favorable tax treatment. Shareholders may be able to use their Fund shares as collateral to meet margin requirements.

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.

Calamos Tax-Aware Collateral ETF

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 State Street^®​ SPDR^®​ S&P 500^®​ ETF Trust (formerly, "SPDR^®​ S&P500^®​ ETF Trust") ("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/resources/doc-viewer#spy&prospectus

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 26, 2026 ("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

Calamos Tax-Aware Collateral ETF

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 December 31, 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.

Calamos Tax-Aware Collateral ETF

• 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

Calamos Tax-Aware Collateral ETF

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

Calamos Tax-Aware Collateral ETF

"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

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/.

Calamos Tax-Aware Collateral ETF

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 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.

You can find the Fund's statutory prospectus and statement of additional information online at https://www.calamos.com/resources/.

Calamos Tax-Aware Collateral ETF

2020 Calamos Court
Naperville, IL 60563-2787
866.363.9219
www.calamos.com
811-22887

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