Any more than taxes are.

The fact remains that is NOT a simple tax.

It IS independent of tax revenue.

It IS a fund.

It DOES invest (in the government) to grow the fund.

It is no more a Ponzi than a bank or an insurance company; unfortunately (or fortunately, given levels of federal corruption), the SSA is limited in how they can invest. These limits limit their profitability. Benefits are calculated (unlike benefits gained through taxation) against what you have personally contributed*.



*there is a lower limit to SSI 'credits'; this does not apply to most recipients