The 15-year annualized return for stable value funds as of March 2023 was 2.99%, according to the non-profit group Stable Value Investment Association (SVIA). The same figure for money market funds was 0.55%. For added context, short bonds have produced a 15-year annualized return of 1.46%, and intermediate bonds, 2.41%.
Note that stable value funds can produce lower returns than money market funds when rates are rising. For example, in the 12 months before March 31, 2023, stable value funds returned 2.37% -- slightly less than the money market returns of 2.41%.
In this case, the lower return for stable value happens because stable value funds adjust to market rates slowly. Money market returns, on the other hand, react to prime rate changes quickly. That can be good or bad for investors, depending on whether rates are falling or rising.