January 12, 2024

Summary Prospectus

Calamos CEF Income & Arbitrage ETF

(NYSE Arca – CCEF)

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 prospectus@calamos.com. The current prospectus and statement of additional information, both dated January 12, 2024 (and as each may be amended or supplemented), are incorporated by reference into this summary prospectus.

Investment Objective

The Calamos CEF Income & Arbitrage ETF's investment objective is high current income and long-term capital appreciation.

Fees and Expenses of the Fund

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

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

Management Fees	0.74	%
Distribution and/or Service Fees (12b-1)	0.00	%
Other Expenses1​	0.00	%
Acquired Fund Fees and Expenses2​	2.00	%
Total Annual Fund Operating Expenses3​	2.74	%

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

2  "Acquired Fund Fees and Expenses" include certain expenses incurred in connection with the Fund's investment in various closed-end funds, exchange-traded funds ("ETFs"), and business development companies ("BDCs"). The amount shown is based on estimated amounts for the current fiscal year.

3  The Total Annual Fund Operating Expenses in this fee table may not correlate to the expense ratios in the Fund's financial highlights and financial statements because the financial highlights and financial statements reflect only the operating expenses of the Fund and do not include Acquired Fund Fees and Expenses, which are fees and expenses incurred indirectly by the Fund through its investments in certain underlying investment companies.

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell or hold 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
	277		850

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 high current income and long-term capital appreciation by investing in unaffiliated closed-end funds that the Fund's investment adviser, Calamos Advisors LLC ("Calamos Advisors" or the "Adviser"), believes offer both attractive income opportunities as well as arbitrage opportunities resulting from such closed-end funds trading at attractive discounts (market prices that are less than the closed-end funds' net asset value ("NAV")). The Fund's strategy seeks to identify closed-end funds trading at attractive discounts and sell such funds when the arbitrage opportunity has either been achieved by capturing the benefit of discount narrowing or when the Adviser determines the discount level no longer represents an unusual divergence from the fund's underlying asset value. Under normal circumstances, the Fund seeks to achieve its investment objectives by investing at least 80% of its net assets (plus borrowings for investment purposes, if any) in U.S. and non-U.S. closed-end funds.

In selecting the closed-end funds for the Fund's portfolio, the Adviser utilizes a combination of quantitative and fundamental tools to identify closed-end funds that are trading at a discount and represent an opportunity for the Fund to achieve its investment objective. In addition, the Adviser considers the Fund's asset allocation, event research (both fund-specific and market-wide), and trading opportunities (i.e., the liquidity profile of a closed-end fund). The Adviser intends to rebalance the portfolio regularly to ensure that the desired asset allocations are maintained.

Calamos CEF Income & Arbitrage ETF

The Adviser will also make active adjustments to the portfolio relative to certain portfolio-level characteristics, that may include, but are not limited to, distribution yield, size of an issue, liquidity and trade execution.

The Fund also may invest in ETFs and business development companies ("BDCs"). Through its investments in closed-end funds, ETFs, and BDCs, the Fund may have exposure to different asset classes, including but not limited to equity securities (U.S. and non-U.S., including emerging markets), fixed income securities (investment grade, high yield, and municipal), convertible securities, derivatives and Master Limited Partnerships ("MLPs"). Fixed income securities may include bonds and debentures that may be rated investment grade or below investment grade or may not be rated, may be issued by corporations, governments or public international bodies and may be denominated in a variety of currencies and issued with either fixed or floating rates. Bonds rated below investment grade are commonly known as "junk bonds."

The Fund may invest in rights or warrants of equity securities and closed-end funds. The Fund also may use derivative instruments such as options, index futures, and forward contracts. The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis.

In order to capture the relative arbitrage value embedded in the discount, the Fund may from time to time take short positions that approximate the value of the underlying closed-end fund assets. The Fund also may take other short positions, including in U.S. treasury futures. The Fund may maintain short positions through the use of derivative instruments, such as options and futures.

The Fund may seek to generate income from option premiums by writing (selling) options. This would include the use of both call and put options. The Fund may write options (i) on a portion of the equity securities (including securities that are convertible into equity securities) in the Fund's portfolio and (ii) on broad-based securities indexes (such as the S&P 500 or MSCI EAFE) or ETFs. In addition, to seek to offset some of the risk of a potential decline in value of certain long positions, the Fund may also purchase put options on individual securities, broad-based securities indexes (such as the S&P 500), or ETFs.

The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act").

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. Risks of investing in the Fund include risks associated with (1) the Fund's investment in closed-end fund shares; (2) the closed-end funds' investments; and (3) any other investments of the Fund, including investments in ETFs, BDCs, and derivative instruments. 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, either directly or through its investments in closed-end funds, include:

•  Anti-Takeover Provisions Risk — The closed-end funds in which the Fund invests may have organizational documents, such as a declaration of trust or by-laws, that include provisions that could limit the ability of the investors in such closed-end funds to acquire control of the closed-end fund or to change the composition of its Board. Such provisions could limit the ability of the Fund to sell such closed-end fund shares at a premium over prevailing market prices by discouraging a third party from seeking to obtain control of the closed-end fund. These provisions may include staggered terms of office for the Trustees, advance notice requirements for shareholder proposals, and super-majority voting requirements for certain transactions with affiliates, converting the Fund to an open-end investment company or a merger, asset sale or similar transaction. Holders of preferred shares of such closed-end funds that have issued preferred shares have voting rights in addition to and separate from the voting rights of common shareholders with respect to certain of these matters. The holders of the closed-end fund debt, on the one hand, and the holders of the common shares, on the other, may have interests that conflict in these situations.

•  Arbitrage Risk — The Fund's use of an arbitrage strategy in order to take advantage of a perceived discount presents certain risks. The shares of the underlying closed-end funds in which the Fund invests may trade at a discount or premium to their NAV. Historically, shares of underlying funds have frequently traded at a discount to their NAV, which discounts have, on occasion, been substantial and lasted for sustained periods of time. This characteristic is a risk separate and distinct from the risk that an underlying fund's NAV could decrease as a result of investment activities. Whether investors, such as the Fund, will realize gains or losses upon the sale of shares will depend not on the underlying funds' NAVs, but entirely upon whether the market price of the underlying funds' shares at the time of sale is above or below an investor's purchase price for shares. Forecasting market movements is difficult, and securities may be mispriced or improperly valued by the Adviser.

•  Authorized Participant Concentration Risk — Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants).

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Calamos CEF Income & Arbitrage ETF

To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem, Fund Shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

•  Business Development Company ("BDC") Risk — The Fund may invest in BDCs, which typically operate to invest in, or lend capital to, early stage-to-mature private companies as well as small public companies. BDCs are regulated under the 1940 Act and are generally taxed as regulated investment companies under the Internal Revenue Code. BDCs realize operating income when their investments are sold off or as income is received in connection with lending, and therefore maintain complex organizational, operational, tax and compliance requirements. For tax purposes, BDCs generally intend to qualify for taxation as regulated investment companies. To so qualify, BDCs must satisfy certain asset diversification and source of income tests and must generally distribute at least 90% of their taxable earnings as dividends. Under the 1940 Act, BDCs are also required to invest at least 70% of their total assets primarily in securities of private companies or thinly traded U.S. public companies, cash, cash equivalents, U.S. government securities and high quality debt investments that mature in one year or less. Generally, little public information exists for private and thinly traded companies in which a BDC may invest, and therefore there is a risk that investors may not be able to make a fully informed decision. In addition, investments made by BDCs are typically illiquid and may be difficult to value. A BDC may only incur indebtedness in amounts such that the BDC's asset coverage, subject to certain conditions, equals at least 150% after such incurrence. These limitations on asset mix and leverage may prohibit the way that the BDC raises capital.

•  Closed-End Funds Risk — The shares of closed-end funds may trade at a discount or premium to, or at, their NAV. The securities of closed-end funds may be leveraged. As a result, the Fund, may be exposed indirectly to leverage through an investment in such securities. An investment in securities of closed-end funds that use leverage may expose the Fund to higher volatility in the market value of such securities and the possibility that the Fund's long-term returns on such securities (and, indirectly, the long-term returns of its shares) will be diminished. In addition, closed-end funds are allowed to invest in a greater amount of illiquid securities than open-end mutual funds. Investments in illiquid securities pose risks related to uncertainty in valuations, volatile market prices, and limitations on resale that may have an adverse effect on the ability of the fund to dispose of the securities promptly or at reasonable prices.

•  Convertible Securities Risk — The value of a convertible security is influenced by changes in interest rates, with investment value declining as interest rates increase and increasing as interest rates decline. The credit standing of the issuer and other factors also may have an effect on the convertible security's investment value. Convertible securities generally offer lower interest or dividend yields than non-convertible fixed-income securities of similar credit quality because of the potential for capital appreciation. In addition, the value of a convertible security is influenced by the interest rate environment, company credit risk, and by the value of the underlying common stock. As the market price of the underlying common stock declines below the conversion price, the price of the convertible security tends to be increasingly influenced by the credit quality, maturity and yield of the convertible security. Holders of convertible securities have a claim on the issuer's assets prior to the common stockholders, but may be subordinated to holders of similar but non-convertible securities of the same issuer.

•  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.

•  Covered Call Writing Risk — 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.

•  Currency Risk — To the extent that the Fund, or a closed-end fund in which the Fund invests, invests in securities or other instruments denominated in or indexed to foreign currencies, changes in currency exchange rates bring an added dimension of risk. Currency fluctuations could negatively impact investment gains or add to investment losses. Although the Fund or a closed-end fund in which the Fund invests may attempt to hedge against currency risk, the hedging instruments may not always perform as the Fund or a closed-end fund in which the Fund invests expects and could produce losses. Suitable hedging instruments may not be available for currencies of emerging market countries. The Adviser, or a closed-end fund's investment adviser, may determine not to hedge currency risks, even if suitable instruments appear to be available.

•  Debt Securities Risk — Debt securities are subject to various risks, including interest rate risk, credit risk and default risk.

•  Interest Rate Risk — The value of debt securities generally decreases in periods when interest rates are rising. In addition, interest rate changes typically have a greater effect on prices of longer-term debt securities than shorter term debt securities. Recent fixed-income market events, including increases in volatility and interest rates, may expose the Fund to heightened interest rate risk and volatility.

•  Credit Risk — A debt security could deteriorate in quality to such an extent that its rating is downgraded or its market value declines relative to comparable securities. Changes in actual or perceived creditworthiness may occur quickly. If the Fund holds securities that have been downgraded, or that default on payment, the Fund's performance could be negatively affected.

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Calamos CEF Income & Arbitrage ETF

•  Default Risk — A company that issues a debt security may be unable to fulfill its obligation to repay principal and interest. The lower a bond is rated, the greater its default risk. To the extent the Fund holds securities that have been downgraded, or that default on payment, its performance could be negatively affected.

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

•  Emerging Markets Risk — Emerging market countries may have relatively unstable governments and economies based on only a few industries, which may cause greater instability. The value of emerging market securities will likely be particularly sensitive to changes in the economies of such countries. These countries are also more likely to experience higher levels of inflation, deflation or currency devaluations, which could hurt their economies and securities markets. Securities issued in these countries may be more volatile and less liquid than securities issued in foreign countries with more developed economies or markets. Loss may also result from the imposition of exchange controls, confiscations and other government restrictions, or from problems in share registration, settlement, custody, or other operational risks.

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

•  ETF Risk — The Fund's investment in shares of ETFs subjects it to the risks of owning the securities underlying the ETF, as well as the same structural risks faced by an investor purchasing shares of the Fund, including authorized participant concentration risk, market maker risk, premium-discount risk and trading issues risk. As a shareholder in another ETF, the Fund bears its proportionate share of the ETF's expenses, subjecting Fund shareholders to duplicative expenses.

•  Foreign Securities Risk — Risks associated with investing in foreign securities include fluctuations in the exchange rates of foreign currencies that may affect the U.S. dollar value of a security, the possibility of substantial price volatility as a result of political and economic instability in the foreign country, less public information about issuers of securities, different securities regulation, different accounting, auditing and financial reporting standards and less liquidity than in U.S. markets.

•  Fund of Funds Risk — Because the Fund is a "fund of funds," its investment performance largely depends on the investment performance of the funds in which it invests. An investment in the Fund is subject to the risks associated with such funds. Therefore, there is a risk that the Fund may suffer losses due to the investment practices or operations of the funds in which it invests. To the extent that the Fund invests in one or more funds that concentrate in a particular type of security or specific industry, the Fund would be exposed to such specific securities' risks and be vulnerable to factors affecting that industry and may cause the Fund to be more volatile than other funds. The funds held by the Fund are not subject to the Fund's investment policies and restrictions. The Fund generally receives information regarding the portfolio holdings of such funds only when that information is made available to the public. The Fund cannot dictate how such funds invest their assets. The funds may invest their assets in securities and other instruments, and may use investment techniques and strategies, that are not described in this disclosure.

The Fund will pay indirectly a proportional share of the fees and expenses of the funds in which it invests (referred to herein as "acquired fund fees and expenses"), including their investment advisory and administration fees, in addition to its own fees and expenses. In addition, at times, certain segments of the market represented by the funds in which the Fund invests may be out of favor and underperform other segments.

•  Futures and Forward Contracts Risk — Futures contracts provide for the future sale by one party and purchase by another of a specific asset at a specific time and price (with or without delivery required). Futures contracts are standardized contracts traded on a recognized exchange. An option on a futures contract gives the purchaser the right, in exchange for a premium, to assume a position in a futures contract at a specified exercise price during the term of the option. Futures and forward contracts are subject to counterparty risk, meaning that the party with whom the Fund enters into the derivatives transaction (the clearinghouse or the broker holding the Fund's position for a futures contract or the counterparty for a forward contract) may experience a significant credit event and/or may be unwilling or unable to make timely settlement payments or otherwise honor its obligations.

•  High Yield Risk — High yield securities and unrated securities of similar credit quality (commonly known as "junk bonds") are subject to greater levels of credit and liquidity risks. High yield securities are considered primarily speculative with respect to the issuer's continuing ability to make principal and interest payments.

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Calamos CEF Income & Arbitrage ETF

•  Large-Capitalization Investing Risk — Large-capitalization stocks as a group could fall out of favor with the market, which may cause a closed-end fund in which the Fund invests to underperform funds that focus on other types of stocks. In addition, larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer preferences. Many larger companies also may not be able to attain the high growth rate of successful smaller companies, especially during extended periods of economic expansion.

•  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. If there is a general decline in the stock or fixed-income market, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests.

•  MLP Risk — Investments in securities of MLPs involve risks that differ from investments in common stock, including risks related to limited control and limited rights to vote on matters affecting the MLP, risks related to the potential conflicts of interest between the MLP and the MLP's general partners, cash flow risks, dilution risks and risks related to the general partners right to require unit holders to sell their common units at an undesirable time or price.

•  MLP Tax Risk — MLPs generally do not pay federal income tax at the partnership level. Rather, each partner is allocated a share of the partnerships' income, gains, losses, deductions and credits. A change in current tax law, or a change in the underlying business of an MLP, could result in an MLP being treated as a corporation, instead of a partnership, for federal income tax purposes, which would result in such MLP being required to pay income tax on its taxable income. This would have the effect of reducing the amount of cash available for distribution by the MLP, potentially reducing the value of the Fund's investment and consequently your investment in the Fund.

•  MLP Liquidity Risk — Although common units of MLPs trade on the NYSE, the NASDAQ and Amex, certain MLP securities trade less frequently than those of larger companies due to their smaller capitalization. As a result, the price of such MLPs may display abrupt and erratic movements at times. Additionally it may be more difficult for the Fund to buy and sell significant amounts of such securities without unfavorable impact on prevailing market process. As a result, these securities may be difficult to dispose of at a fair price when the Adviser desires to do so. This may adversely affect the Fund's ability to take advantage of other market opportunities or make dividend distributions.

•  Equity Securities of MLPs Risk — MLP common units, like other equity securities, can be affected by macro-economic and other factors affecting the stock market in general, expectations of interest rates, investor sentiment towards an issuer or certain market sector, changes in a particular issuer's financial condition, or unfavorable or unanticipated poor performance of a particular issuer (in the case of MLPs, generally measured in terms of distributable cash flow). Prices of common units of individual MLPs, like the prices other equity securities, also can be affected by fundamentals unique to the partnership or company, including earnings power and coverage ratios.

•  Municipal Securities Risk — The Fund may invest in closed-end funds and/or ETFs that hold municipal securities. Issuers, including governmental issuers, may be unable to pay their obligations as they come due. The values of municipal securities that depend on a specific revenue source to fund their payment obligations may fluctuate as a result of actual or anticipated changes in the cash flows generated by the revenue source or changes in the priority of the municipal obligation to receive the cash flows generated by the revenue source. The values of municipal securities held by an underlying fund may be adversely affected by local political and economic conditions and developments. Adverse conditions in an industry significant to a local economy could have a correspondingly adverse effect on the financial condition of local issuers. In addition, income from municipal securities held by an underlying fund could be declared taxable because of, among other things, unfavorable changes in tax laws, adverse interpretations by the Internal Revenue Service or state tax authorities, or noncompliant conduct of an issuer or other obligated party. Loss of tax-exempt status may cause interest received and distributed to shareholders by an underlying fund to be taxable and may result in a significant decline in the values of such municipal securities. Due to the COVID-19 pandemic, the risks of the municipal securities market have been magnified. The costs associated with combating the pandemic and the negative impact on tax revenues has adversely affected the financial condition of many states and political subdivisions. These risks may also adversely affect several sectors of the municipal bond market, such as airports, toll roads, hospitals and colleges, among many others. The full impact of the COVID-19 pandemic on state and political subdivisions' ability to make payments on debt obligations is impossible to predict, but could negatively impact the value of bonds, the ability of state and political subdivisions to make payments when due and the performance of the Fund.

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Calamos CEF Income & Arbitrage ETF

•  National Closed Market Trading Risk — To the extent that the underlying securities and/or other assets held by the Fund trade on non-U.S. exchanges or in non-U.S. markets that may be closed when the securities exchange on which Fund Shares trade is open, there are likely to be deviations between the current price of such an underlying security and the last quoted price for the underlying security (i.e., the Fund's quote from the closed non-U.S. market). The impact of a closed foreign market on the Fund is likely to be greater where a large portion of the Fund's underlying securities and/or other assets trade on that closed non-U.S. market or when the non-U.S. market is closed for unscheduled reasons. These deviations could result in premiums or discounts to the Fund's NAV that may be greater than those experienced by other ETFs.

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

•  Non-Diversification Risk — The Fund is classified as "non-diversified" under the 1940 Act. As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended.

•  Options Risk — The Fund's ability to close out its position as a purchaser or seller of an over-the-counter or exchange-listed put or call option is dependent, in part, upon the liquidity of the option 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.

•  Other Investment Companies (including closed-end funds, ETFs and BDCs) Risk — The Fund invests in the securities of other investment companies (including closed-end funds, ETFs, and BDCs) consistent with the Fund's investment objective and the policies are permissible under the 1940 Act. Investments in the securities of other investment companies may involve duplication of advisory fees and certain other expenses. Additionally, if the investment company fails to achieve its investment objective, the value of the Fund's investment will decline, adversely affecting the Fund's performance. In addition, closed-end funds, ETF, and BDC shares potentially may trade at a discount or a premium and are subject to brokerage and other trading costs, which could result in greater expenses to the Fund. Whether the Fund will realize a gain or loss upon the sale of the such shares of closed-end funds, ETFs and BDCs depends upon whether the market value of the shares at the time of sale is above or below the price the Fund paid, taking into account transaction costs for the shares, and is not directly dependent upon the NAV of the shares of such funds. Because the market value of the shares will be determined by factors such as the relative demand for and supply of the shares in the market, general market conditions and other factors, it cannot be predicted whether such shares will trade at, below or above NAV, or below or above the public offering price for the shares. Common Shares, as well as shares issued by the closed-end funds, do not assure dividend payments. Dividends are paid only when declared by the boards of directors of the closed-end funds, and the level of dividends may vary over time. If a closed-end fund reduces or eliminates the level of its regular dividends, this may reduce the level of dividends paid by the Fund, and may cause the market prices of the closed-end fund's shares to fall.

In accordance with Section 12(d)(1)(F) of the 1940 Act, on which the Fund intends to rely to invest in other investment companies, the Fund will be restricted by provisions of the 1940 Act that limit the amount the Fund can invest in any one investment company to 3% of the investment company's total outstanding stock. As a result, the Fund may hold a smaller position in an investment company than if it were not subject to this restriction. However, if the Adviser determines that it is in the Fund's best interest to exceed the 3% limit, it may rely on Rule 12d1-4 under the 1940 Act. Rule 12d1-4 would permit the Fund to invest in excess of the 3% limit subject to certain conditions, including that the Fund must enter into a "Fund of Funds Investment Agreement" with the acquired investment company setting forth the material terms of the arrangement. In addition, to comply with provisions of the 1940 Act, on any matter upon which investment company stockholders are solicited to vote, the Adviser will vote investment company shares in the same general proportion as shares held by other stockholders of the investment company (a practice known as "echo voting"). This could limit the Fund's ability to support or oppose investment company shareholder voting matters.

•  Portfolio Selection Risk — The value of your investment may decrease if Calamos Advisors' judgment about the attractiveness, value or market trends affecting a particular security, issuer, industry or sector or about market movements is incorrect.

•  Portfolio Turnover Risk — The portfolio managers may actively and frequently trade securities or other instruments in the Fund's portfolio to carry out its investment strategies. A high portfolio turnover rate increases transaction costs, which may increase the Fund's expenses. Frequent and active trading may also cause adverse tax consequences for investors in the Fund due to an increase in short-term capital gains.

•  Premium-Discount Risk — Fund Shares may trade above or below their net asset value ("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. In addition, trading in Fund Shares on the Exchange may be halted.

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Calamos CEF Income & Arbitrage ETF

•  Sector Risk — To the extent the Fund 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 Fund may underperform the broader market or experience greater volatility.

•  Short Sale Risk — The Fund may incur a loss (without limit) as a result of a short sale if the market value of the borrowed security (i.e., the Fund's short position) increases between the date of the short sale and the date the Fund replaces the security. The Fund may be unable to repurchase the borrowed security at a particular time or at an acceptable price.

•  Tax Risk — The federal income tax treatment of securities in which the Fund may invest 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 regulated investment companies 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 regulated investment companies could cause the Fund to fail to qualify as such.

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

Fund Performance

The Fund had not commenced operations as of the date of this prospectus. Once available, the Fund's performance information, and information that gives some indication of the risks of an investment in the Fund by comparing the Fund's performance with a broad measure of market performance, will be available on 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
R. Matthew Freund	Since January 2024	SVP, Sr. Co-Portfolio Manager
Shaheen Iqubal	Since January 2024	SVP, Associate Portfolio Manager

Other Important Information Regarding Fund Shares

Portfolio Holdings. The Fund's portfolio holdings are disclosed on its website daily after the close of trading on the Exchange and prior to the opening of trading on the Exchange the following day. A description of the Fund's policies and procedures with respect to the disclosure of 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/.

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Calamos CEF Income & Arbitrage 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 expects to declare and distribute its net investment income, if any, to shareholders as dividends monthly. The Fund may distribute such investment income more frequently, if necessary, in order to reduce or eliminate federal excise or income taxes on the Fund. The Fund expects to declare and distribute capital gains, if any, on an annual basis.

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 CEF Income & Arbitrage ETF

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

CCEFSUMPRO 011224

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