Do you have an additional tax amount on Schedule 2 line 8 with the box for Form 8960 checked on that line? If so, that's Net Investment Income Tax. It's an additional 3.8% tax on investment income above a certain amount.
Net Investment Income Tax applies if your Modified Adjusted Gross Income (MAGI) is more than $200,000 for single or head of household, $250,000 for married filing jointly or qualifying widow(er), or $125,000 for married filing separately.
