By the time tax season closed in April, the Social Security Administration had pushed more than 3.1 million payments totaling roughly $17 billion out to former public employees whose benefits were once reduced by the Windfall Elimination Provision (WEP) or Government Pension Offset (GPO). For many recipients, that money arrived as a single lump sum covering back benefits as far back as January 2024 — and for the first time, that retroactive total showed up on their 2025 SSA-1099.
It also pushed a meaningful number of retirees into higher tax brackets, larger IRMAA Medicare surcharges, and steeper Social Security inclusion rates than they would otherwise have faced. A little-known IRS option — the lump-sum election method — was designed for exactly this situation, and many recipients did not learn about it until after they filed.
What the Lump-Sum Election Actually Does
When Social Security pays benefits attributable to prior years, IRS Publication 915 lets recipients calculate the taxable portion as if each year's share had been received in that earlier year. The election does not require filing amended returns for those prior years. Instead, you recalculate what the tax impact would have been in each applicable year using that year's income and brackets, then report only the smaller of the two results on this year's return.
For retirees who had lower incomes in 2024 or 2025 than in the current year — common for those who deferred Social Security while collecting only a non-covered pension — the savings can be substantial. The election is made by checking a box on Form 1040 or 1040-SR and attaching the supporting worksheet.
Who This Matters Most For
Affected recipients tend to fall into a few patterns:
- Public-sector retirees with bracket shifts. Teachers, firefighters, and police officers whose total taxable income rose sharply in the year the lump sum arrived.
- Couples crossing the IRMAA cliff. A one-year income spike from back pay can trigger Medicare Part B and Part D surcharges two years later — even if income returns to normal.
- Survivors receiving multi-year retroactive amounts. Widows and widowers who never collected restored spousal or survivor benefits may have received the largest back-pay totals.
If You Already Filed Without Making the Election
The election can be added by filing an amended return on Form 1040-X. The three-year statute of limitations for refund claims typically runs from the original return's due date, so 2025 returns filed in April 2026 generally remain amendable through April 2029. Pulling the SSA-1099, the lump-sum breakdown letter from SSA showing which years the payments cover, and prior-year tax returns is the starting point.
What's Still Ahead
Roughly a year after the Fairness Act was signed, some recipients are still waiting for full benefits while SSA works through complex cases, according to reporting from Government Executive. A separate proposal in Congress would eliminate federal income tax on the restored back payments entirely, but it has not been enacted. Until — and unless — that bill becomes law, the lump-sum election remains the most reliable tool for limiting the tax cost of catching up on benefits the system originally withheld.
For retirees who built diversified income plans around the assumption of a predictable Social Security stream, the lesson is broader: a single oversized taxable year can ripple into Medicare premiums, Roth conversion capacity, and capital-gains brackets. Reviewing the timing — not just the amount — of any large retirement payment is worth the hour it takes.
Sources: Social Security Administration, CNBC, Kiplinger, Government Executive, IRS Publication 915