CALVERT GREEN BOND FUND CLASS R6 (CBGRX) Exchange: NMFQS

Under normal circumstances, the Fund invests at least 80% of its net assets (including borrowings for investment purposes) in “green” bonds (“80% Policy”). Bonds include debt securities of any maturity. The Fund typically invests at least 65% of its net assets in investment grade debt securities, as assessed at the time of purchase. A debt security is considered investment grade when assigned a credit quality rating of BBB- or higher by S&P Global Ratings (“S&P”) or an equivalent rating by another nationally recognized statistical rating organization (‘‘NRSRO“), including Moody’s Investors Service, Inc. or Fitch Ratings, or if unrated, considered to be of comparable credit quality by the Fund’s investment adviser. For purposes of rating restrictions, if securities are rated differently by two or more rating agencies, the highest rating is used. The Fund primarily invests in a broad range of fixed-income securities, including, but not limited to, corporate bonds, project bonds, bonds issued by the U.S. government or its agencies, and U.S. government-sponsored enterprises (“GSEs”) such as the Federal National Mortgage Association (“FNMA”) and the Federal Home Loan Mortgage Corporation (“FHLMC”). The Fund may also invest in taxable municipal obligations. The Fund may invest in below-investment grade, high-yield debt instruments (commonly known as “junk bonds”), including distressed instruments that are in default. The Fund may invest in asset-backed securities (“ABS”) and mortgage-backed securities (“MBS”) that represent interests in pools of mortgage loans (MBS) or other assets (ABS) assembled for sale to investors by various U.S. governmental agencies, government-related organizations and private issuers. MBS may include collateralized mortgage obligations (“CMOs”) and commercial mortgage-backed securities (“CMBS”). The Fund may also invest in foreign debt securities. Foreign debt securities include sovereign debt and American Depositary Receipts (“ADRs”). The Fund may engage in forward foreign currency exchange contracts to seek to hedge against the decline in the value of currencies in which its portfolio holdings are denominated against the U.S. dollar. The portfolio managers generally seek to hedge the Fund’s foreign currency exposure back to U.S. dollars, though the Fund may at any time have exposure to foreign currency. The Fund seeks to invest primarily in “green” investments. The Fund defines “green” investments to include securities of companies that develop or provide products or services that seek to provide environmental solutions and/or support efforts to reduce their own environmental footprint; bonds that support environmental projects; structured securities that are collateralized by assets supporting environmental themes; and securities that, in the opinion of the Fund’s investment adviser, have no more than a negligible direct environmental impact, which may include securities issued by the U.S. government or its agencies, and U.S. government-sponsored entities. The Fund may also lend its securities. Investment decisions for the Fund are made primarily on the basis of fundamental and quantitative research conducted by the investment adviser’s research staff and consideration of the responsible investment criteria described below. Management of the Fund involves consideration of numerous factors (such as quality of business franchises, financial strength, management quality and security structural and collateral considerations). The portfolio managers may also use sector rotation strategies in their management of the Fund. The portfolio managers may sell a security when the investment adviser’s valuation target is reached, the fundamentals of the investment change or to pursue more attractive investment options. A security will also be sold (in accordance with the investment adviser’s guidelines and at a time and in a manner that is determined to be in the best interests of shareholders) if the investment adviser determines that the issuer does not operate in a manner consistent with the Fund’s responsible investment criteria. The portfolio managers intend to focus on risk management and also seek to preserve capital to the extent consistent with the Fund’s investment objectives. The Fund intends to seek to manage investment risk by maintaining broad issuer and industry diversification among its holdings, and by utilizing fundamental analysis of risk/return characteristics in securities selection. The Fund seeks to manage duration and any hedging of interest rate risk through the purchase and sale of U.S. Treasury securities and related futures contracts (which are a type of derivative instrument). Responsible Investing. In selecting investments for the Fund, CRM is guided by The Calvert Principles for Responsible Investment (a copy of which is included as an appendix to this Prospectus), which provide a framework for considering environmental, social and governance (“ESG”) factors that may affect investment performance.