The fund pursues its investment objective by investing its assets primarily in fixed-income securities, such as U.S. treasury bonds, notes and bills, treasury inflation-protected securities, U.S. treasury Strips, U.S. government agency securities, and investment grade corporate debt rated BBB or higher by Standard & Poor's Global Ratings or Baa or higher by Moody's Investors Service, Inc., or having an equivalent rating from another independent rating organization.