The Congressional Budget Office (CBO), in its September 2026 forecasts, projects that Social Security (OASI) faces a shortfall of 4.55 percent of taxable payroll. The Social Security Administration also projected earlier this year that Social Security faces a shortfall of 4.55 percent of taxable payroll. This is a departure from previous years, when the CBO has typically projected a larger long-term shortfall than the Social Security Administration, and thus warrants a closer look.
Our analysis finds that much of the decline in CBO’s headline estimate reflects higher projected interest rates, which change how future shortfalls are valued in net present value terms. The smaller estimated payroll tax gap does not imply that the actual financing shortfall, the difference between what Social Security collects and what it is scheduled to pay, has narrowed.