Assuring Medicare’s Promise Act of 2025

H.R. 609 would make changes to how Medicare is funded by modifying the Net Investment Income Tax (NIIT). The bill would direct revenues from the Net Investment Income Tax into the Medicare Hospital Insurance Trust Fund, which funds hospital care for seniors and disabled individuals. Currently, these tax revenues go to the general Treasury rather than directly to Medicare.

The bill would also expand the Net Investment Income Tax to apply to business income for high-income individuals, defined as those with modified adjusted gross income exceeding $400,000 (or $500,000 for joint filers). This would require wealthy business owners to pay the 3.8% Medicare tax on their business earnings in addition to investment income. The changes would take effect for tax years beginning after December 31, 2025. Supporters argue the bill would extend Medicare's solvency and ensure higher-income earners pay their fair share into the program, while opponents may argue it increases taxes on business owners and investors.