Taxable wages and/or self-employment income under the prevailing annual maximum taxable limit.

Weighted average of taxable wages and taxable self-employment income. When multiplied by the combined employee-employer tax rate, it yields the total amount of taxes incurred by employees, employers, and the self-employed for work during the period.

Net earnings from self-employment, generally above $400 and below the annual maximum taxable amount for a calendar or other taxable year, less any taxable wages in the same taxable year.

Salaries paid for services rendered in covered employment up to the annual maximum taxable amount.

Beginning in 1994, up to 85% of an individual’s or a couple’s OASDI benefits is potentially subject to federal income taxation under certain circumstances. The revenue derived from taxation of benefits in excess of 50%, up to 85%, is allocated to the health insurance trust fund.