"[A] single premium immediate annuity (SPIA) provides a lifetime stream of income that by definition cannot be outlived, and the potential for long-lived retirees to earn mortality credits creates the potential to earn significantly more cumulative return than what bonds alone can pay.... While it's true that for extreme longevity scenarios, SPIAs provide an unparalleled return and enhance retirement outcomes, the strategy as commonly implemented is also an indirect form of a bucket strategy that disproportionately liquidates fixed-income assets in the early years and lets the rest of the (risky) portfolio run. By reducing withdrawals from risky assets in the early years, the exposure to potentially unfavorable return sequences is diminished, even as the total allocation to equities rises throughout retirement."  MORE >>