The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80% of its assets in a diversified portfolio of mortgage-related Fixed Income Instruments of varying maturities (such as mortgage pass-through securities,collateralized mortgage obligations,commercial mortgage-backed securities, and mortgage dollar rolls), which may be represented by forwards or derivatives such as options, futures contracts or swap agreements. Fixed Income Instruments include bonds, debt securities and other similar instruments issued by various U.S. and non-U.S. public- or private-sector entities. The average portfolio duration of this Fund normally varies from one to seven years based on PIMCOs market forecasts. Duration is a measure used to determine the sensitivity of a securitys price to changes in interest rates. The longer a securitys duration, the more sensitive it will be to changes in interest rates