"[S]ubstituting [single premium immediate annuities] for investment-grade bonds appears to be almost unambiguously sound. However, the competition tightens considerably when using bonds to generate total return rather than for income alone. That is, instead of clipping bond coupons while retaining principal, our retiree in effect creates her own annuity by dipping into capital. Doing so would sharply increase her sustainable withdrawal rate."  MORE >>