On March 9, 2023, the U.S. Department of the Treasury released the Greenbook (formally known as the General Explanations of the Administration’s Revenue Proposals), to explain the revenue proposals included in Administration’s budget. One proposal in the Administration’s budget would increase the additional Medicare tax rate by 1.2 percentage points for high-income taxpayers.
Self-employment earnings and wages are subject to employment taxes under either the Self-Employment Contributions Act (SECA) or the Federal Insurance Contributions Act (FICA). Both SECA and FICA taxes apply at a rate of 12.4 percent for social security tax on self-employment earnings and wages (capped at $160,200 in 2023) and at a rate of 2.9 percent for Medicare tax on all self-employment earnings and wages (not subject to a cap). In the case of FICA taxes, the employee and employer each pay half of the taxes imposed on wages.