The same thing is true of your investment account. When you buy bonds you're giving money to a company or the US Treasury who then spend it. That money is gone.

The same thing is true of your investment account. When you buy bonds you're giving money to a company or the US Treasury who then spend it. That money is gone. You're assuming the borrower will choose pay you back from some future revenue stream. When you buy into a stock IPO you're betting that the company will pay you dividends from a future revenue stream (or do related things that make the stock perceived as valuable.) In the case of Social Security that future revenue stream is taxes drawn from the US taxpayer. None of this is a Ponzi scheme.