NET INVESTMENT TAX
There is a 3.8% additional tax for investment income (ordinary dividends, interest, annuities from non-qualified plans, royalties, net rental income & capital gains) when the modified adjusted gross income is over $250,000 for married filing joint ($200,000 if single or head of household, $125,000 if married filing separate). That is the bottom line of the front of your personal tax return AGI less some adjustments for foreign taxes (the literature refers to this as MAGI (Modified Adjusted Gross Income).
Let’s assume in computing TAXABLE income of $255,000 we used itemized deductions and personal exemptions totaling $30,000. So, the AGI = $460,000.
Let’s assume the ONLY investment income is the above example of $175,000 LTCG.
In the above example, the tax might apply to $460,000 – $250,000 = $210,000. BUT, since LTCG is $175,000, the tax applies only to the $175,000. Again, this assumes the only investment income is the $175,000 LTC