What Is an Annuity? Fixed Income Payouts Explained

An annuity is a contract with an insurance company: you hand over a lump sum (or a series of payments) upfront, and in exchange the insurer promises to pay you back over time — often as a fixed stream of income for the rest of your life. The core trade is converting a pile of money you might outlive into a stream of income you can’t outlive, with the insurer bearing the risk of paying out longer than expected in exchange for keeping the money if you don’t live as long as average.

The basic mechanics

An annuity has two phases. During the accumulation phase, money goes in — either as a single lump-sum premium or through periodic contributions — and typically grows tax-deferred, meaning no tax is owed on the growth until money is withdrawn. During the payout (annuitization) phase, the insurer starts sending money back, either immediately or starting at some future date the contract specifies.

Payouts can be structured several ways: for a fixed number of years, for the rest of your life (life annuity), for the longer of your life or your spouse’s (joint-and-survivor), or with a guaranteed minimum number of payments even if the annuitant dies early (period certain). The insurer prices the contract using actuarial life-expectancy tables — the same underlying discipline that prices life insurance — so a life annuity purchased at 65 pays a smaller monthly amount than one purchased at 80, because the insurer expects to make payments for longer.

Immediate vs deferred annuities

• Immediate annuities start paying out almost right away, typically within a year of the lump-sum premium. These are common for someone at or near retirement who wants to convert a portion of savings directly into guaranteed income.
• Deferred annuities accumulate for years before payouts begin, functioning more like a tax-deferred savings vehicle in the meantime. Someone in their 40s or 50s might buy a deferred annuity specifically for the accumulation phase’s tax treatment, planning to annuitize decades later.

Fixed, variable, and indexed annuities

The other major distinction is how the money grows during accumulation, and how much market risk the buyer is exposed to:

	Fixed annuity	Variable annuity	Indexed annuity
Growth basis	Guaranteed fixed rate, set by the insurer	Underlying investment subaccounts (like mutual funds)	Tied to an index (e.g. the S&P 500), often with a cap and floor
Market risk	None — insurer bears it	Borne by the buyer	Partial — downside is usually floored, upside is usually capped
Return potential	Low but predictable	Higher, but variable and could lose value	Moderate, bounded on both ends
Complexity	Low	High (fees, subaccount choices)	Moderate to high (cap/floor/participation-rate mechanics)

A fixed annuity functions much like a certificate of deposit with a longer horizon and an insurer instead of a bank: a set rate, no market exposure, and a predictable outcome. A variable annuity puts the buyer’s money into investment subaccounts that behave like mutual funds, meaning the payout depends on market performance — more upside potential, but also real risk of loss, layered under insurance fees that a plain brokerage account wouldn’t charge. An indexed annuity sits between the two: returns are tied to an index’s performance, but usually with a cap limiting the maximum gain and a floor (often 0%) limiting the maximum loss, in exchange for lower fees than a variable annuity and lower guaranteed growth than a fixed one.

What annuities are actually for

The core problem an annuity solves is longevity risk — the risk of outliving your savings. A 401(k) or an IRA is a pot of money you draw down yourself, and if you live longer than your withdrawal plan anticipated, you can run out. A life annuity removes that risk entirely for the portion of savings annuitized: the payments continue regardless of how long you live, because the insurer is pooling that risk across many annuity holders — some will die earlier than average, some later, and the insurer prices the product so the pool balances out.

This insurance function is the annuity’s real value proposition, distinct from its role as an investment. Judged purely as an investment, an annuity often compares unfavorably to a diversified portfolio held over the same period, especially once fees and surrender charges are accounted for — but that comparison misses the point, since a portfolio provides no insurance against outliving it. The two are solving different problems, and evaluating an annuity purely on expected return misses why buyers purchase one in the first place.

Fees and surrender charges

Annuities are frequently criticized for cost, and often deservedly: variable annuities in particular can carry mortality and expense (M&E) fees, administrative fees, and subaccount management fees stacked on top of each other, in addition to fees for optional riders like a guaranteed minimum income benefit. Most annuities also impose a surrender charge — a penalty for withdrawing money within a set number of years (commonly 5–10) after purchase, which declines gradually and eventually disappears. This makes an annuity a genuinely illiquid commitment for that period; money placed in one shouldn’t be money you might need access to on short notice.

The takeaway

An annuity converts savings into a stream of income, insuring against the risk of outliving your money by pooling that risk across many contract holders. Fixed annuities trade market risk for a guaranteed rate, variable annuities pass market risk to the buyer in exchange for growth potential, and indexed annuities land in between with a capped, floored return tied to an index. The product is best understood as insurance against longevity risk first and an investment second — evaluating it purely on expected return, without weighing what it insures against, misses why it exists.