Messrs Feldstein and Samwick also assume that retired folk will convert their personal retirement accounts into a variable-rate annuity, based on a combination of stocks and bonds, rather than a fixed-rate annuity.
Returns on these investments vary fairly widely based on whether they're subject to early withdrawal penalties, offer fixed or variable yields, or are protected by deposit insurance.
The subpoena comes amid increasing scrutiny of whether large brokerages have received secret payments from insurance companies to sell variable annuities, which offer both a death benefit and a financial return based on how well the investments inside them perform.