The funds can include Treasuries, Mortgage Backed Securities (MBS), TIPS or other debt instruments sponsored by the U.S. government or its agencies
With maturities longer than 10 years, or durations of more than 6 years, the funds will usually offer higher yields than shorter duration bonds, but they will also be more sensitive to interest rate risk
With the potential to generate income, and price appreciation, the funds remain exposed to inflation risk - the performance of inflation-protected funds stands out while zero-coupon bonds are most sensitive to rate increases