- Your net investment income
- The amount of your modified adjusted gross income (basically, your adjusted gross income increased by an amount associated with any foreign earned income exclusion) that exceeds $200,000 ($250,000 if married filing a joint federal income tax return, and $125,000 if married filing a separate return)
So if you're single and have a MAGI of $250,000, consisting of $150,000 in earned income and $100,000 in net investment income, the 3.8% tax will only apply to $50,000 of your investment income.
The 3.8% tax also applies to estates and trusts. The tax is imposed on the lesser of undistributed net investment income or the excess of MAGI that exceeds the top income tax bracket threshold for estates and trusts ($12,150 in 2014). This relatively low tax threshold potentially could affect estates and trusts with undistributed income. Consult a tax professional.
What is net investment income?
Net investment income generally includes all net income (income less any allowable associated deductions) from interest, dividends, capital gains, annuities, royalties, and rents. It also includes income from any business that's considered a passive activity, or any business that trades financial instruments or commodities.
Net investment income does not include interest on tax-exempt bonds, or any gain from the sale of a principal residence that is excluded from income. Distributions you take from a qualified retirement plan, IRA, 457(b) deferred compensation plan, or 403(b) retirement plan are also not included in the definition of net investment income.
The information presented here is not specific to any individual's personal circumstances. To the extent that this material concerns tax matters, it is not intended or written to be used, and cannot be used, by a taxpayer for the purpose of avoiding penalties that may be imposed by law. Each taxpayer should seek independent advice from a tax professional based on his or her individual circumstances.
These materials are provided for general information and educational purposes based upon publicly available information from sources believed to be reliable—we cannot assure the accuracy or completeness of these materials. The information in these materials may change at any time and without notice.