Normally investing at least 80% of assets in debt securities rated below investment grade (also referred to as high yield debt securities or junk bonds). Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  Below investment grade debt securities are debt securities that are rated below BBB- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO), or, if unrated, determined by the Adviser to be of comparable quality. Derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives. Using the ICE® BofA® BB-B US High Yield Constrained Index as a guide in structuring the fund and selecting its investments as it relates to credit quality distribution and risk characteristics. Normally investing primarily in securities rated BB or B by Standard & Poor's (S&P), Ba or B by Moody's Investors Service (Moody's), comparably rated by at least one nationally recognized credit rating agency, or, if unrated, considered by Fidelity Management & Research Company LLC (FMR) to be of comparable quality. Potentially investing in securities that have a higher or lower credit quality. Investing in companies in troubled or uncertain financial condition. Investing in domestic and foreign issuers. Generally utilizing a research-driven approach identifying long-term drivers of high yield debt security returns that may include, but are not limited to, valuation, quality, momentum, and other factors. The research is systematically applied alongside a proprietary portfolio construction and risk management framework to select a broadly diversified group of high yield debt securities that may have the potential to provide a higher total return than that of the ICE® BofA BB-B US High Yield Constrained Index.