Discussions in the United States regarding the funding gap in social security are once again bringing the idea of "raising the cap on social security payroll taxes for high-income earners" to the forefront of policy. In the past, this proposition mainly came from Democrats, but now some Republican lawmakers have also begun to publicly express their willingness to consider it, giving it more attention at the bipartisan level.

Currently, the Social Security payroll tax in the United States is only levied on wages within a set ceiling. Once income exceeds this ceiling, there is no further payment of this tax on the excess amount. This means that high-income individuals often only contribute to the social security system for a portion of the year.

Members of both parties begin to soften their stance

In June of this year, Republican Senator Bernie Moreno and Democratic Senator Elizabeth Warren jointly wrote an article advocating for raising the cap on social security payroll taxes, calling it a more direct solution. Subsequently, Republican Representatives Tom Cole and Lloyd Smucker also expressed their willingness to consider supporting the measure by increasing payroll taxes.

The backdrop for this change is that the payment pressures on social security funds are approaching. According to the annual report released by the trustees in June, retirement trust funds may not be able to pay benefits in full as promised as early as the fourth quarter of 2032, and at that time, only about 78% of the planned benefits will be able to be paid.

If the retirement trust fund and the disability trust fund are combined for calculation, the full payment can be extended to the third quarter of 2034, but by then only about 83% of the benefits will be able to be paid.

How much gap can it fill?

How much of the funding gap can be made up by increasing the tax base depends on the specific plan. According to the Roosevelt Institute, if the upper limit on taxable wages is set to cover 90% of the total national wage bill in the long term, 28% of the payment gap over the next 75 years could be filled without increasing benefits; if monthly benefits are also increased simultaneously, the filling ratio would be about 22%.

Another more radical proposal is to eliminate the current wage tax cap for incomes over $400,000. A 2024 survey conducted on behalf of the National Academy of Social Insurance, AARP, the National Institute on Retirement Security, and the American Chamber of Commerce found that this option received the highest level of support among the surveyed adults.

Researchers say that about 6% of workers earn more than the current annual income limit each year. Over their entire careers, only about 20% of workers ever exceed this threshold at some point.

The controversy focuses on the economic costs.

Supporters believe that removing the cap could significantly alleviate the pressure on social security funds without a widespread increase in taxes. Opponents, however, argue that this would be equivalent to imposing an additional 12.4 percentage points of wage tax on the currently tax-exempt portion, with the burden falling primarily on a minority of high-income individuals.

The Tax Foundation stated that such adjustments would constitute one of the largest tax increases since 1982. The organization warned that high-income individuals might reduce their work, adjust their salary structures, or underreport taxable wages as a result, thereby weakening the effectiveness of the policy.

According to calculations by the Tax Foundation, if the wage tax cap is raised to $346,000 starting in 2027 and this cap covers 90% of total wages, the number of jobs in the United States could decrease by nearly 900,000, and the gross domestic product (GDP) could fall by 0.7%. If the cap were completely eliminated and taxes were levied on all wages, the impact could be even greater.

Opponents also pointed out that, against the backdrop of the U.S. federal debt exceeding $40 trillion, if taxes are significantly increased for high-income individuals first, the government's room for further tax increases in other areas such as healthcare and fiscal deficits may become even more limited in the future.