What Are Mortality Credits? Annuity Glossary

How mortality credits work

When you put money into a lifetime income annuity, your premium is pooled together with everyone else who bought the same kind of contract, and the insurance company commits to paying every one of them for as long as they each live. Not everyone in that pool lives to the same age, of course. The money that would have kept flowing to people who pass away earlier than expected does not disappear. It stays inside the pool and helps fund the payments still owed to the people who live longer. That internal transfer, moving from shorter lifespans to longer ones, is what actuaries label a mortality credit.

Why mortality credits matter

No CD, bond, or personally managed account can reproduce this kind of pooling, which is exactly why a properly priced immediate annuity or other annuitized income stream can pay out more, guaranteed, than you could safely withdraw from a portfolio of the same size on your own. Mortality credits also grow larger the older you are when income begins, since a shorter expected payout period concentrates more of the pool's support into each remaining year. This is one reason a single premium immediate annuity purchased at 75 tends to pay a noticeably higher share of the deposit each year than the same contract bought at 65. It is not that the carrier is favoring older buyers; the math of the pool simply rewards a shorter expected payout window. That single mechanic, more than any tax feature, is the reason lifetime income annuities exist at all. It also explains why comparing a single premium immediate annuity purely on its stated payout rate misses the point. Two contracts can quote different percentages and still be priced fairly once you account for how each insurer models its own pool of policyholders, their expected lifespans, and current interest rates. A licensed strategist can walk you through how those assumptions shape the number you are actually quoted.