He Delayed Social Security to 70 for the 8% Raise and Lived on His IRA. By 73, the Smaller IRA Meant a Smaller RMD, Too.

Delaying Social Security to age 70 is usually pitched as a single-lever move: a bigger monthly check for life. The version of the strategy this article presents adds a second, quieter benefit. The retiree who spends down an IRA between 62 and 70 not only locks in a larger benefit, but also shrinks the account balance that required minimum distributions will later be measured against. Both effects run in the same direction, and both survive cost-of-living adjustments once they start.

Verifying the 8% Figure

Delayed retirement credits are the increases the Social Security Administration adds to a benefit for each month someone waits to claim past full retirement age, the age at which a worker can receive an unreduced benefit based on the primary insurance amount, which is the formula-based benefit calculated from lifetime earnings. For workers born in 1943 or later, the credit accrues at 8% per year, or two-thirds of 1% per month, and it stops entirely at age 70. Waiting past 70 gains nothing.

The 8% is applied to the primary insurance amount and is then carried forward through every future cost-of-living adjustment, or COLA, the annual inflation increase that Social Security applies to benefits already in payment. The 2027 COLA is tracking toward 3.1% with one of three Q3 months in, based on data as of July 1, 2026. A benefit boosted by 32% by four years of delay is a benefit that all future COLAs will compound off of.

Verifying the Age 73 RMD

A required minimum distribution, or RMD, is the amount the IRS forces retirees to withdraw each year from a traditional IRA once they reach the required beginning date. Under SECURE 2.0, that date is age 73 for individuals born between 1951 and 1959, and age 75 for those born in 1960 or later. Someone reaching 70 in the current period falls into the 73 cohort, so the headline is internally consistent, but a reader born in 1960 or later will not face an RMD until age 75.

Why the IRA Bridge Compounds

Every RMD is calculated as the prior year-end IRA balance divided by an IRS life-expectancy factor. Every dollar withdrawn between 62 and 70 to replace a Social Security check is a dollar that is not in the balance when the divisor is applied at 73. The bridge does two things at once: it buys a larger, inflation-adjusted lifetime benefit, and it shrinks the taxable distribution the IRS will later require.

The opportunity cost of leaving IRA assets in cash-like instruments during the bridge is visible in current rates. The 10-year Treasury yield was 4.75% on August 31, 2026, while the FDIC national average 12-month CD rate was 1.71% APY as of August 1, 2026. The gap matters when the same IRA is funding eight years of spending.

Counterweights to Consider

• Bridge withdrawals are taxable. Every dollar pulled from a traditional IRA between 62 and 70 is ordinary income in the year taken. The strategy shifts the timing of the tax bill.
• Provisional income does not disappear. Provisional income is the formula Social Security uses to decide how much of a benefit is taxable. A larger benefit at 70 means more benefit dollars potentially exposed to that calculation later.
• It requires a large IRA. Funding eight years of spending from an IRA is not available to retirees whose balances are too small to cover the gap.
• It is a longevity bet. Someone in poor health may collect more by claiming earlier. Married couples should also weigh the survivor benefit, the amount a surviving spouse receives, because delaying the higher earner’s claim raises what the survivor keeps for life.
• Roth conversions compete for the same brackets. The bridge years are prime Roth conversion territory, and bridge withdrawals and conversions both fill up the same low-bracket space (we sized up that gap between the last paycheck and the first RMD in a free guide: The Roth Window).

What the Data Supports

The 8% credit, the age 70 ceiling, and the age 73 required beginning date are the three anchors of the strategy, and each is defined by statute rather than markets. The second benefit, a smaller IRA feeding a smaller RMD, is arithmetic that follows from spending the account down before the IRS begins measuring it. Whether the trade is worth it depends on the size of the IRA, the retiree’s health, marital status, and how the same bracket space might otherwise have been used for Roth conversions.

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