A Penn Wharton Budget Model (PWBM) analysis says a transfer to cover Social Security’s post-reserve shortfall could score at zero against the Congressional Budget Office (CBO) scheduled-benefit baseline, depending on the bill’s provisions and the budget measure used.
That result rests on a budget accounting rule, not a source of money. Under 2 U.S.C. § 907(b)(1), baseline calculations must assume entitlement programs have enough funding to make payments required by law. CBO’s baseline therefore counts scheduled benefits after reserves are exhausted, although program income would not be enough to pay them fully and on time.
PWBM says the rule is a scorekeeping instruction; it does not provide financing or borrowing authority. Congress would need to authorize a way to supply the missing funds, and a bill’s score depends on its provisions and the budget measure used.
Forecasts vary by fund and model. The 2026 OASDI Trustees Report projects the Old-Age and Survivors Insurance (OASI) fund’s reserves will run out in the fourth quarter of 2032, when income would cover 78% of benefits. The trustees put combined OASI and Disability Insurance (DI) fund depletion in 2034, with income covering about 83% of costs; that estimate assumes a change in law allowing transfers between the separate funds.
PWBM’s September 2026 baseline projects OASI depletion in February 2033 and combined-fund depletion in February 2035, when income would cover about 85% of scheduled benefits. That estimate compares projected income with scheduled costs; it does not specify how individual payments would be handled. In a separate illustration, CBO estimates benefit reductions totaling $2.7 trillion over fiscal 2032-36 before economic effects, including a 7% reduction in 2032 and an average 28% reduction each year from 2033 through 2036.
PWBM estimates that borrowing post-depletion shortfalls at the trust funds’ interest rate and financing the interest would leave accumulated financing needs by 2100 equal to 201.77% of that year’s gross domestic product (GDP) and 485.37% of taxable payroll. The ratios compare cumulative financing with 2100 annual totals and describe PWBM’s scenario, not a CBO debt forecast. If borrowing financed transfers, scheduled payments could continue while the government took on the related financing needs and interest.
The 2026 OASDI Trustees Report also projects retired-worker numbers will rise about 60% over the next 50 years, while the number of workers paying Social Security taxes per beneficiary falls from 2.6 in 2025 to 2.3 in 2035. The Social Security Administration (SSA) summary of the report points to birth rates and net immigration below historical levels.
The trustees list revenue increases, benefit changes or a combination of the two, and urge action early enough to phase changes in. A Congressional Research Service (CRS) account hosted by SSA traces a precedent to the 1983 amendments, which combined revenue and benefit changes after a bipartisan commission process.
