HP 30b Built-in MIRR and FMRR Functions.
The HP 30b comes with MIRR (Modified Internal Rate of Return) and Financial Management Rate of Return (FMRR). Both of these function take care of the problem found in basic IRR that occurs when the signs of cash flows switch from negative to positive to negative. MIRR and FMRR provide one rate of return that more accurately reflects the return an investor receives. They differ on how they manipulate any negative cash flows after the initial cash outlay.