Actually the Social Security Fund is a separate account. Funds collected are used to pay out benefits due. Excess money go into the general fund for which a government bond is issued to SSA. When not enough SS taxes come in to pay for benefits these bonds are used to make up the difference.
For the last 30 something years SS trust fund income has exceeded outgo.
This year or next that will change and difference will be made up with interest on government bonds owned by SS. Eventually this will disappear and the fund will no longer have any reserve to draw on. It is projected that this will happen by 2034. If no action is taken by the government it is estimated at that time that benefits will be reduced to around 76% of what people had been getting. That money would be coming from the current SS taxes and be paid immediately back out to beneficiaries.
Here's a graph.
View attachment 213851
Here is a more complete synopsis:
How Do the Trust Funds Work?
Social Security’s financial operations are handled through two federal trust funds — the Old-Age and Survivors Insurance (OASI) trust fund and the Disability Insurance (DI) trust fund. Although legally distinct, they are often referred to collectively as “the Social Security trust fund.” All of Social Security’s payroll taxes and other earmarked income are deposited in the trust funds, and all of Social Security’s benefits and administrative expenses are paid from the trust funds.
Social Security is largely a “pay as you go” program, meaning
today’s benefits are funded primarily by the payroll taxes collected from today’s workers. For over three decades, however, Social Security collected more in payroll taxes and other income than it paid in benefits and other expenses, and t
he Treasury invested the surplus in interest-bearing Treasury securities, ultimately reaching a total of nearly $2.9 trillion in trust fund reserves. In 2021, Social Security will begin redeeming those reserves to help pay benefits.
Payroll taxes from current workers will continue to pay for the bulk of benefits. The trust fund reserves will make up the difference between income and costs until the reserves are depleted. At that point, Social Security’s income will still be able to pay 79 percent of promised benefits — even in the unlikely event that policymakers fail to act.
What Is the Trust Funds’ Financial Status?
If Social Security’s trust funds run out of Treasury bonds to cash in, benefits would not stop — contrary to a common misunderstanding.
Social Security is adequately financed in the short term but faces a modest long-term financial shortfall amounting to about 1 percent of gross domestic product (GDP) over the next 75 years, the period that the program’s actuaries use in evaluating the program’s long-term finances.
Following the bipartisan Social Security financing deal in 1983, Social Security has run a surplus every year, and will continue to do so until 2021.
Starting in 2021, Social Security’s total cost will exceed its total income. However, the trust funds’ reserves will supplement the program’s income — from payroll taxes, income taxes on benefits paid to higher-income beneficiaries, and interest earned on the trust funds’ bonds — to enable Social Security to keep paying full benefits until 2035.
If Social Security’s trust funds run out of Treasury bonds to cash in, benefits would not stop — contrary to a common misunderstanding. At that point, if nothing else is done, Social Security could still pay 79 percent of promised benefits using its annual tax income. Of course, paying less than full benefits is not an acceptable way to run this vital program, and Congress will need to act to strengthen its long-term finances.
Most analyses of Social Security focus on the combined OASI and DI trust funds, since both are integral parts of Social Security, but the two trust funds are, in fact, separate. The DI trust fund faces exhaustion in 2065, and the much larger OASI fund is projected to last until 2034.