Americans are socking away record sums in bank accounts. But they are leaving money on the table.

Savings and money-market deposit accounts at U.S. financial institutions held $7.3 trillion at the end of March, according to an analysis of Federal Reserve data by Moebs Services, an economic research firm in Lake Bluff, Ill. Another $1.6 trillion was sitting in checking accounts. Both figures are all-time highs, though neither is adjusted for inflation.

The catch: The accounts often pay mere pennies in interest. Savings accounts carry an average annual yield of 0.08%, the lowest since at least 1984, according to Bankrate.com, a bank-account comparison website. Checking accounts yield an average of 0.06%, and many pay nothing at all.

Jittery depositors often favor savings and checking accounts and certificates of deposit because the Federal Deposit Insurance Corp. insures balances up to certain limits.

Yet there are ways to get the same protection while generating extra income. In some cases, that could mean hunting down accounts that pay higher interest. In other cases, that could mean considering alternatives, such as prepaid cards.