A non-money market fund's SEC yield is based on a formula mandated by the Securities and Exchange Commission (SEC) that calculates a fund's hypothetical annualized income, as a percentage of its assets. A security's income, for the purposes of this calculation, is based on the current market yield to maturity (in the case of bonds) or projected dividend yield (for stocks) of the fund's holdings over a trailing 30 day period. This hypothetical income will differ (at times, significantly) from the fund's actual experience; as a result, income distributions from the fund may be higher or lower than implied by the SEC yield.
The SEC yield for a money market fund is calculated by annualizing its daily income distributions for the previous seven days.