March 1, 2021, as amended September 17, 2021

Summary Prospectus

Calamos Hedged Equity Fund

NASDAQ Symbol: CAHEX - Class A CCHEX - Class C CIHEX - Class I

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 https://www.calamos.com/resources/. You can also get this information at no cost by calling 800.582.6959 or by sending an e-mail request to [email protected]. The current prospectus dated March 1, 2021, as amended September 17, 2021, and statement of additional information dated March 1, 2021, as amended June 30, 2021 (and as each may be amended or supplemented), and the financial statements included in the Fund's recent report to shareholders, dated October 31, 2020, are incorporated by reference into this summary prospectus.

Investment Objective

Calamos Hedged Equity Fund's investment objective is to seek total return with lower volatility than equity markets.

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. Investors may pay other fees, such as brokerage commissions and/or other forms of compensation to a financial intermediary, which are not reflected in the tables or the examples below. You may qualify for sales charge discounts on purchases of Class A shares if you and your family invest, or agree to invest in the future, at least $50,000 in Calamos Funds. More information about these and other discounts is available from your financial professional and under 'Fund Facts - What classes of shares do the Funds offer?' on page 129 of the Fund's prospectus, in the Appendix to this prospectus and 'Share Classes and Pricing of Shares' on page 87 of the Fund's statement of additional information.

Shareholder Fees (fees paid directly from your investment):

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

1 'Acquired Fund Fees and Expenses' include certain expenses incurred in connection with the Fund's investment in various money market funds and ETFs.

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then either redeem or do not redeem your shares at the end of the reflected time periods. The example also assumes that your investment has a 5% return each year, that all dividends and capital gain distributions are reinvested, that you pay a maximum initial or contingent deferred sales charge and that the Fund's operating expenses remain the same. Although your actual performance and costs may be higher or lower, based on these assumptions, your costs would be:

You would pay the following expenses if you redeemed your shares at the end of the period:

HEIPRO 09/21

Calamos Hedged Equity Fund

You would pay the following expenses if you did not redeem your shares:

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 the annual fund operating expenses or in the example, affect the Fund's performance. During the Fund's most recent fiscal year, the Fund's portfolio turnover rate was 56.9% of the average value of its portfolio.

Principal Investment Strategies

The Fund seeks to achieve total return with lower volatility than equity markets. Under normal circumstances, the Fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in equity securities and securities with economic characteristics similar to stock or the equity markets. The Fund invests in a broadly diversified portfolio of equity securities while also writing (selling) index call and put options and/or entering into other options strategies on equity securities and/or broad based indices. The Fund may write call options (i) on a portion of the 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 (exchange traded funds).

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 may also engage in active and frequent trading of portfolio securities.

Equity securities purchased by the Fund may include U.S. exchange-listed common stocks, options on equities, and American Depositary Receipts (ADRs). The Fund may also invest in fixed-income securities. The Fund may also invest in ETFs.

The Fund may use derivatives for hedging (attempting to reduce risk by offsetting one investment position with another) or non-hedging purposes. In particular, the Fund may hedge some or all of the currency exposure of foreign securities by entering into forward foreign currency contracts, futures or other derivatives.

The Fund's investment adviser seeks to lower the risks of investing in stocks by using a 'top-down approach' of diversification by company, industry, sector, country and currency and focusing on macro-level investment themes. The Fund intends that its option-based risk management strategy will reduce the volatility inherent in investments in equity securities over time.

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. 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 of investing in the Fund include:

• American Depositary Receipts Risk - The stocks of most foreign companies that trade in the U.S. markets are traded as American Depositary Receipts (ADRs). U.S. depositary banks issue these stocks. Each ADR represents one or more shares of foreign stock or a fraction of a share. The price of an ADR corresponds to the price of the foreign stock in its home market, adjusted to the ratio of the ADRs to foreign company shares. Therefore while purchasing a security on a U.S. exchange, the risks inherently associated with foreign investing still apply to ADRs.

• 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.

• Correlation Risk - The effectiveness of the Fund's index option-based risk management strategy may be reduced if the performance of the Fund's equity portfolio does not correlate to that of the indices underlying its option positions.

• 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 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 may attempt to hedge against currency risk, the hedging instruments may not always perform

Calamos Hedged Equity Fund

as the Fund expects and could produce losses. Suitable hedging instruments may not be available for currencies of emerging market countries. The 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. If the Fund holds securities that have been downgraded, or that default on payment, the Fund's performance could be negatively affected.

• 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 counter party risk, meaning that the party with whom the Fund enters into a derivative transaction may experience a significant credit event and/or may be unwilling or unable to make timely settlement payments or otherwise honor its obligations. Changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index, and the Fund could lose more than the principal amount invested.

• Equity Securities Risk - The securities markets are volatile, and the market prices of the 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 the Fund (i.e., the Fund's long position) fall, the value of your investment in the Fund will decline.

• 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.

• Forward Foreign Currency Contract Risk - Forward foreign currency contracts are contractual agreements to purchase or sell a specified currency at a specified future date (or within a specified time period) at a price set at the time of the contract. The Fund may not fully benefit from, or may lose money on, forward foreign currency transactions if changes in currency exchange rates do not occur as anticipated or do not correspond accurately to changes in the value of the Fund's holdings.

• 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.

• 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 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. The Fund may also purchase or write over-the-counter put or call options, which involves risks different from, and possibly greater than, the risks associated with exchange-listed put or call options. In some instances, over-the-counter put or call options may expose the Fund to the risk that a counterparty may be unable or unwilling to perform according to a contract, and that any deterioration in a counterparty's creditworthiness could adversely affect the instrument. In addition, the Fund may be exposed to a risk that losses may exceed the amount originally invested.

• Other Investment Companies (including ETFs) Risk - The Fund may invest in the securities of other investment companies to the extent that such investments are consistent with the Fund's investment objective and the policies are permissible under the 1940 Act. Under the 1940 Act, the Fund may not acquire the securities of other domestic or non-U.S. investment companies if, as a result, (1) more than 10% of the Fund's total assets would be invested in securities of other investment companies, (2) such purchase would result in more than 3% of the total outstanding voting securities of any one Investment company being held by the Fund or (3) more than 5% of the Fund's

Calamos Hedged Equity Fund

total assets would be invested in any one investment company. These limitations do not apply to the purchase of shares of money market funds or of any investment company in connection with a merger, consolidation, reorganization or acquisition of substantially all the assets of another investment company, or to purchases of investment companies done in accordance with SEC exemptive relief or rules. Investments in the securities of other investment companies, including ETFs, may involve duplication of advisory fees and certain other expenses. Additionally, if the investment company or ETF 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 investment company and ETF 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. In addition, the Fund may engage in short sales of the securities of other investment companies. When the Fund shorts securities of another investment company, it borrows shares of that investment company which it then sells. The Fund closes out a short sale by purchasing the security that it has sold short and returning that security to the entity that lent the security.

• Portfolio Selection Risk - The value of your investment may decrease if the investment adviser's 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.

• Rule 144A Securities Risk - The Fund may invest in securities that are issued and sold through transactions under Rule 144A of the Securities Act of 1933. Under the supervision of its board of trustees, the Fund will determine whether Rule 144A Securities are illiquid. If qualified institutional buyers are unwilling to purchase these Rule 144A Securities, the percentage of the Fund's assets invested in illiquid securities would increase. Typically, the Fund purchases Rule 144A Securities only if the Fund's adviser has determined them to be liquid. If any Rule 144A Security held by the Fund should become illiquid, the value of the security may be reduced and a sale of the security may be more difficult.

• 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.

• Securities Lending Risk - The Fund may lend its portfolio securities to broker-dealers and banks in order to generate additional income for the Fund. Any such loan must be continuously secured by collateral in cash or cash equivalents maintained on a current basis in an amount at least equal to the market value of the securities loaned by the Fund. In the event of bankruptcy or other default of a borrower of portfolio securities, the Fund could experience both delays in liquidating the loan collateral or recovering the loaned securities and losses, including (a) possible decline in the value of the collateral or in the value of the securities loaned during the period while the Fund seeks to enforce its rights thereto, (b) possible subnormal levels of income and lack of access to income during this period, and (c) expenses of enforcing its rights. In an effort to reduce these risks, the Fund's securities lending agent monitors, and reports to Calamos Advisors on, the creditworthiness of the firms to which a Fund lends securities. The Fund may also experience losses as a result of a diminution in value of its cash collateral investments.

• Tax Risk - The federal income tax treatment of convertible securities or other 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.

Fund Performance

The following bar chart and table indicate the risks of investing in the Fund by showing changes in the Fund's performance from calendar year to calendar year and how the Fund's average annual total returns compare with those of a broad measure of market performance. All returns include the reinvestment of dividends and distributions. As always, please note that the Fund's past performance (before and after taxes) cannot predict how it will perform in the future. Updated performance information is available at no cost by visiting www.calamos.com or by calling 800.582.6959.

Calamos Hedged Equity Fund

CLASS I* ANNUAL TOTAL RETURN FOR YEARS ENDED 12.31

* Annual returns for Class I are provided because Class I shares represent the largest percentage of assets in the Calamos Family of Funds.

Average Annual Total Returns as of 12.31.20

The following table shows how the Fund's average annual performance (before and after taxes) for the one- and five-year periods ended December 31, 2020 and since the Fund's inception compared with broad measures of market performance. 'Since Inception' returns shown for each index are returns since the inception of the Fund's Class A shares, or since the nearest subsequent month end when comparative index data is available only for full monthly periods. The after-tax returns show the impact of assumed federal income taxes on an investment in the Fund. 'Return After Taxes on Distributions' shows the effect of taxable distributions, but assumes that you still hold the Fund shares at the end of the period and so do not have any taxable gain or loss on your investment. 'Return After Taxes on Distributions and Sale of Fund Shares' shows the effect of taxable distributions and any taxable gain or loss that would be realized if the Fund shares were purchased at the beginning and sold at the end of the specified period.

The after-tax returns are shown only for Class I shares, and are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their Fund shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns for classes other than Class I will vary from returns shown for Class I. 'Return After Taxes on Distributions and Sale of Fund Shares' may be higher than other returns for the same period due to a tax benefit of realizing a capital loss on the sale of Fund shares.

AVERAGE ANNUAL TOTAL RETURNS - FOR THE PERIODS ENDED 12.31.20

* Returns after taxes for Class I are provided because Class I shares represent the largest percentage of assets in the Calamos Family of Funds.

The Bloomberg U.S. Aggregate Bond Index shows how the Fund's performance compares to an index that covers the U.S.-denominated, investment-grade, fixed-rate, taxable bond market of SEC-registered securities. The index includes bonds from the Treasury, Government-Related, Corporate, MBS (agency fixed-rate and hybrid ARM pass-throughs), ABS, and CMBS sectors.

Calamos Hedged Equity Fund

Investment Adviser

Calamos Advisors LLC

Other Important Information Regarding Fund Shares

For important information about purchase and sale of Fund shares, tax information, and financial intermediary compensation, please turn to 'Other Important Information Regarding Fund Shares' on page 109 of the prospectus.

Buying and Redeeming Fund Shares

Minimum Initial Investment

Classes A and C: $2,500/$500 for IRA
Class I: $1,000,000

Minimum Additional Investment

Classes A and C: $50
Class I: None

To Place Orders

Please contact your broker, benefit plan record-keeper, or other intermediary, or to place your order directly, contact the Fund's transfer agent, U.S. Bank Global Fund Services, toll-free at the number noted below for further instructions:
U.S. Bank Global Fund Services
P.O. Box 701
Milwaukee, WI 53201
Phone: 800.582.6959

Transaction Policies

The Funds' shares are redeemable. In general, investors may purchase, redeem, or exchange Fund shares on any day the New York Stock Exchange is open by written request (to the address noted above), by wire transfer, by telephone (at the number noted above), or through a financial intermediary, depending on how the shares are held. Orders to buy and redeem shares are processed at the next net asset value (share price or 'NAV') to be calculated only on days when the New York Stock Exchange is open for regular trading.

Class I may not be available for purchase directly from the Funds. Please contact us at 800.582.6959 to inquire further about such availability.

Tax Information

The Funds' distributions will generally be taxable as ordinary income or capital gains, except when your investment is in an IRA, 401(k) or other tax-advantaged investment plan. Any distributions from a retirement account or 401(k) plan may be taxed as ordinary income when withdrawn from such account or plan. Special tax rules apply to investments held through defined contribution plans and other tax-qualified plans.

Calamos Hedged Equity Fund

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of a 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.

Click here to view the Fund's statutory prospectus or statement of additional information.

2020 Calamos Court
Naperville, IL 60563-2787
800.582.6959
www.calamos.com
811-05433