Under legislation enacted in 1983, the Social Security Trust Funds receive income based on Federal income taxation of benefits. The funds receive taxes on up to 50 percent of benefits from single taxpayers with incomes over $25,000 and from taxpayers filing jointly with incomes over $32,000.
Legislation enacted in 1993 extended taxation of benefits. The legislation increased the limitation on the amount of benefits subject to taxation from 50 percent to 85 percent for single taxpayers with incomes over $34,000 and for taxpayers filing jointly with incomes over $44,000. All additional tax income resulting from the 1993 legislation is deposited in Medicare's Hospital Insurance Trust Fund.