Term · Single Premium Immediate Annuity

SPIA

Published May 9, 2026

Definition

A SPIA — Single Premium Immediate Annuity — is an annuity contract purchased with a single lump-sum premium that immediately begins paying a guaranteed income stream for life (or for a specified period). Unlike deferred annuities, a SPIA has no cash value, no surrender option, and no rider complexity. It is the simplest and most actuarially transparent annuity product.

A SPIA is an income product, not an investment product. The customer trades a lump-sum premium today for a guaranteed monthly income for the rest of their life — exchanging principal access for longevity protection. The income amount is fixed at issue based on the customer's age, gender (in non-Sex-Discrimination jurisdictions), prevailing interest rates, and the income-form election (life only, life with period certain, joint and survivor).

SPIAs serve a specific function in retirement-income planning: they provide a guaranteed income floor that complements Social Security and other lifetime-income sources. A retiree using SPIAs as part of an income-flooring strategy purchases enough lifetime income to cover essential expenses, with the remaining portfolio invested for growth and discretionary spending. The strategy works because SPIA pricing is competitively priced — insurance companies underwrite the longevity risk efficiently across cohorts.

For wealth-tech platforms, SPIAs are simpler to model than deferred annuities. There's no cash-value tracking, no rider mechanics, no surrender-schedule decay. The data shape is essentially the income amount, the start date, the income form, and the exclusion-ratio for tax purposes (the portion of each payment that's tax-free return of basis). The platform's projection engine treats the SPIA as a fixed cash-flow stream rather than a balance-and-return computation.

SPIAs are tax-treated under IRC §72. For SPIAs purchased outside qualified accounts (the typical case), each payment is split into a basis-return portion (non-taxable) and an earnings portion (taxable). The exclusion ratio is computed at issue based on the premium and the expected total payments under the specific income form. SPIAs purchased inside qualified accounts (rare but real) follow §72(t) rules and are typically fully taxable.

Formula

SPIA exclusion ratio

ExclRatio = Premium / Expected_Total_Payments

Premium: = single premium paid for the SPIA
Expected_Total_Payments: = annual income × IRS-table expected lifetime in years

Example

Premium $250,000. Annual income $18,384 ($1,532/mo). IRS expected lifetime at 65: 20.0 years. Expected total: $367,680. Exclusion ratio = $250,000 / $367,680 = 68.0%. First-year tax-free portion: $18,384 × 0.68 = $12,501. Taxable portion: $5,883. After premium recovery (~year 13.5), 100% of payments are taxable.

Why this matters for synthetic data

SPIA-aware synthetic data needs the contract-level fields: issue date, premium amount, monthly income, income form, exclusion ratio, period certain (if any). The longitudinal projection treats the SPIA as a fixed cash flow rather than a balance-return computation. Test data has to include households with SPIA holdings to exercise the income-stream-fixed projection logic that's qualitatively different from the balance-projection logic for other accounts.

Common pitfalls

Treating SPIA as having a cash value — there isn't one once issued; the customer cannot surrender or borrow against it.
Modeling the SPIA payment as fully taxable — the exclusion-ratio mechanics make a portion tax-free, which affects the after-tax income calculation.
Forgetting period-certain features — life-with-period-certain SPIAs continue payments to a beneficiary if the participant dies during the period; the data shape includes the beneficiary entry.
Confusing SPIA with deferred annuity in surrender period — SPIAs have no surrender; the income is irrevocable.

Examples

65-year-old male SPIA pricing (illustrative)

Premium: $250,000. Income form: life only. Issue date: 2025-09-15. Annuitant: 65-year-old male, non-smoker. Monthly income: approximately $1,532 (about 7.4% annualized payout rate at current rates). Expected total payments over 20-year life expectancy: ~$367,680. Exclusion ratio: $250,000 / $367,680 = 68.0%, meaning 68% of each payment is tax-free return of basis until basis is fully recovered (typically 13-14 years), then 100% taxable.

Frequently asked questions

Why not just take systematic withdrawals from an IRA instead of a SPIA?+

The SPIA pools longevity risk across all participants, allowing higher withdrawal rates than self-managed sustainable-withdrawal strategies. A 4% sustainable withdrawal rate from a self-managed IRA typically requires substantial buffer for longevity uncertainty; a SPIA at age 65 can pay 6-7% because the insurer can rely on cohort-average mortality. The SPIA's higher payout rate is the longevity-pooling premium.

What happens to the principal if I die early?+

Under a 'life only' SPIA, the insurer keeps the remaining principal — which is part of why life-only SPIAs have higher monthly income than period-certain or refund options. Life with period certain (5, 10, 20 years) ensures payments continue to a beneficiary if the annuitant dies during the period; the trade-off is a lower monthly income. Cash-refund SPIAs return any unrecovered principal to the beneficiary at death; the income reduction is similar to period-certain.

Are SPIAs inflation-protected?+

Most SPIAs are nominal — payments don't increase. Inflation-adjusted SPIAs (with COLA features) exist but are uncommon and have meaningfully lower starting payments. Real-world inflation-protected income for retirees typically comes from Social Security (which has a CPI-based COLA); supplementing with nominal SPIAs and real-asset-protected portfolio assets is more common than buying inflation-adjusted SPIAs.