However, one such investment tool has (thus far) offered a guaranteed real-money return , as long as one criterion is met: the SPDR S&P 500 ETF (NYSEMKT: SPY) . This is to bring your attention to the fact that while many of these investments will generate a positive nominal return, not all of them have sufficiently outperformed inflation over time. Money held in a bank is generally protected by the Federal Deposit Insurance Corporation, and the U.S. government has yet to fail to meet an interest payment or fully redeem a maturing bond.