Strategy. Under normal circumstances, the Fund invests at least 80% of its net assets (including borrowings for investment purposes) in bonds (80% Policy). Bonds include debt securities of any maturity. At least 80% of the Funds net assets are invested in investment grade debt securities. 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 Moodys Investors Service, Inc. or ?Fitch Ratings, or Kroll Bond Rating Agency, LLC for securitized debt instruments only (such as asset-backed securities (ABS) and mortgage-backed securities (MBS)) or if unrated, considered to be of comparable credit quality by the Funds investment … Show more… Under normal circumstances, the Fund invests at least 80% of its net assets (including borrowings for investment purposes) in bonds (80% Policy). Bonds include debt securities of any maturity. At least 80% of the Funds net assets are invested in investment grade debt securities. 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 Moodys Investors Service, Inc. or ?Fitch Ratings, or Kroll Bond Rating Agency, LLC for securitized debt instruments only (such as asset-backed securities (ABS) and mortgage-backed securities (MBS)) or if unrated, considered to be of comparable credit quality by the Funds 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 invests principally in bonds issued by ?U.S. corporations, 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 also may invest in trust preferred securities, taxable municipal obligations and loans. The Fund may invest in ?ABS and 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 invest up to 20% of its net assets in below-investment grade, high-yield debt instruments (commonly known as junk bonds), including distressed instruments that are in default. The Fund may also invest up to 25% of its net assets in foreign debt securities, including securities and instruments that are tied to emerging market countries and currencies. Foreign debt securities include American Depositary Receipts (ADRs), which are either sponsored or unsponsored. 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 Fund may purchase securities on a when-issued basis and for future delivery by means of forward commitments. The Fund may invest in money market instruments. The Fund may also lend its securities. The Fund may invest in derivative instruments, such as options, futures contracts (including index futures contracts), foreign forward currency exchange contracts or swap agreements (including credit default swaps). The use of these derivative transactions may allow the Fund to obtain net long or short exposures to select currencies, interest rates, countries, duration or credit risks. These derivatives may be used to seek to hedge against fluctuations in securities prices, interest rates, or currency exchange rates, enhance Fund returns, increase liquidity and/or gain exposure to certain instruments or markets (e.g., the corporate bond market) in a more efficient way. Investment decisions for the Fund are made primarily on the basis of fundamental and quantitative research conducted by the investment advisers 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 and relative value strategies in their management of the Fund. The portfolio managers may sell a security when the investment advisers 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 advisers 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 Funds responsible investment criteria. The portfolio managers intend to focus on risk management and also seek to preserve capital to the extent consistent with the Funds investment objective. 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. The portfolio manager(s) seek to invest in companies that manage environmental, social and governance (ESG) risk exposures adequately and that are not exposed to excessive ESG risk through their principal business activities. Companies are analyzed by the investment advisers ESG analysts utilizing The Calvert Principles for Responsible Investment (Principles), a framework for considering ESG factors (a copy of which is included as an appendix to the Funds Prospectus). Each company is evaluated relative to an appropriate peer group based on material ESG factors as determined by the investment adviser. Pursuant to the Principles, the investment adviser seeks to identify companies and other issuers that operate in a manner that is consistent with or promotes environmental sustainability and resource efficiency, equitable societies and respect for human rights, and accountable governance and transparency. The Fund generally invests in issuers that are believed by the investment adviser to operate in accordance with the Principles and may also invest in issuers that the investment adviser believes are likely to operate in accordance with the Principles pending the investment advisers engagement activity with such issuer. Show less