Low-interest rates
As with the majority of other savers, the Social Security program benefits from the well-known high interest rates. Money paid into the whole Social Security system is invested in all kinds of bonds and other high-quality securities that also pay interest.
As rates are rising, the Social Security program earns even more, which means that it becomes even more solvent. Even so, rates marked a persistent low in the last couple of years; even if they’ve risen, they still don’t increase enough or for long enough, which means that the Social Security program might have to recalibrate itself with lower income for its own beneficiaries.