IRS.gov.

Tax rates include the 3.8% Net Investment Income Tax (NIIT) that is applied to investment income if your overall modified adjusted gross income (MAGI) is above $200,000 for single filers or head of household, $125,000 for married filing separately, and $250,000 for married filing jointly or a qualifying widow(er) with a dependent child. This is often referred to as the "Medicare surtax" and is layered on top of the other income tax rate you owe on that income.

*Up to a 20% tax rate on net capital gains applies to the extent that a taxpayer's taxable income for 2023 exceeds $578,125 for single filers, $693,750 for married filing jointly or qualifying widow(er), $578,100 for head of household, and $346,875 for married filing separately.