Summary Prospectus by Investment Company (Form 497K)

March 5, 2025, as amended October 16, 2025

Summary Prospectus

Calamos Growth Fund

NASDAQ Symbol: CVGRX - Class A CVGCX - Class C CGRIX - 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 and statement of additional information, both dated February 28, 2025 (and as each may be amended or supplemented), and the financial statements included in the Fund's recent report to shareholders, dated October 31, 2024, are incorporated by reference into this summary prospectus.

Investment Objective

Calamos Growth Fund's investment objective is long-term capital growth.

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 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 151 of the Fund's prospectus, in the Appendix to this prospectus and "Share Classes and Pricing of Shares" on page 73 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):

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:

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

GROPRO 101625

Calamos Growth Fund

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 most recent fiscal year, the Fund's portfolio turnover rate was 42% of the average value of its portfolio.

Principal Investment Strategies

The Fund invests primarily in equity securities issued by U.S. companies. The Fund currently anticipates that substantially all of its portfolio will consist of securities of companies with large and mid-sized market capitalizations. The Fund's investment adviser generally defines a large cap company to have a market capitalization in excess of $25 billion and a mid-sized company to have a market capitalization greater than $1 billion, up to $25 billion. The Fund may invest up to 25% of its net assets in foreign securities. Foreign securities are securities issued by issuers that are organized under the laws of a foreign country or that have a substantial portion of their operations or assets in a foreign country or countries, or that derive a substantial portion of their revenue or profits from businesses, investments or sales outside of the United States. The Fund may also invest in foreign securities that are represented in the United States securities markets by American Depositary Receipts ("ADRs") or similar depository arrangements. The Fund's foreign debt investments can be denominated in U.S. dollars or in foreign currencies. Debt securities issued by a foreign government may not be supported by the "full faith and credit" of that government. The Fund may also invest in privately placed securities, including in third-party private funds ("Private Funds") that themselves invest in equity securities of privately held companies subject to applicable limits under the 1940 Act.

In pursuing its investment objective, the Fund seeks out securities that, in the investment adviser's opinion, offer the best opportunities for growth. The Fund's investment adviser typically considers the company's financial soundness, earnings and cash flow forecast and quality of management. 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.

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 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:

• 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.

• 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 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.

• Growth Stock Risk - Growth securities typically trade at higher multiples of current earnings than other securities and, therefore, may be more sensitive to changes in current or expected earnings than other equity securities and may be more volatile.

• Mid-Sized Company Risk - Mid-sized company stocks have historically been subject to greater investment risk than large company stocks. The prices of mid-sized company stocks tend to be more volatile than prices of large company stocks.

• 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

Calamos Growth Fund

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.

• 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.

• 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.

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.

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 12.31.24

The following table shows how the Fund's average annual performance (before and after taxes) for the one-, five- and ten-year periods ended December 31, 2024 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.

Calamos Growth Fund

AVERAGE ANNUAL TOTAL RETURNS - FOR THE PERIODS ENDED 12.31.24

1 All index returns include the reinvestment of dividends and distributions net of withholding taxes, but do not reflect fees, brokerage commissions, or other expenses.

2 The Fund's investment adviser added the broad-based securities market index in accordance with recent changes to regulatory disclosure requirements. The Fund continues to use the S&P 1500 Growth Index as an additional benchmark because the investment adviser believes it is more representative of the Fund's investment universe than the broad-based securities market index. The S&P 1500 Growth Index is a composite index that includes securities that account for 90% of the total market capitalization of the U.S.'s stocks. The index includes small, mid and large cap stocks. The S&P 1500 Growth Index is a subset of the securities appearing in the S&P 1500 Index, which includes the S&P 500, S&P 400, and S&P 600 indices. The S&P 1500 Growth Index is designed to provide investors with a measure of the performance of U.S. growth equities. The S&P 500 Total Return Index is provided as it is generally representative of the U.S. stock market.

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

Investment Adviser

Calamos Advisors LLC

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:
Calamos Family of Funds
c/o U.S. Bank Global Fund Services
PO Box 219252
Kansas City, MO 64121-9252
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, except as otherwise provided herein (see the "Transaction Information - Share Price" section in the Fund's prospectus for more information).

Calamos Growth Fund

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.

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.

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

2020 Calamos Court
Naperville, IL 60563-2787
800.582.6959
www.calamos.com
811-05443