Grand Junction · Taxes with "Medicare" in the name

Is the 3.8% Net Investment Income Tax a Medicare Tax?

A Grand Junction couple sells a rental house in Fruita, and their tax preparer mentions a "3.8% Medicare surtax" on part of the gain. The natural next question is whether that money goes toward their Medicare, or earns them anything from it. The short answer is no on both. The longer answer is worth knowing, because the Medicare cost that sale actually triggers is a different bill, and a bigger one.

Medicare On Main Data Desk

Published October 14, 2026 · 8 min read · Reviewed by Brian Penner, 22+ years in Medicare

Where the "Medicare" in the name comes from

The tax was created by the 2010 health care legislation and took effect January 1, 2013. Congress placed it in a chapter of its own, Chapter 2A of the Internal Revenue Code, and titled that chapter "Unearned Income Medicare Contribution." Its one section, 26 U.S.C. § 1411, sets the tax at 3.8 percent of the lesser of net investment income or the amount by which modified adjusted gross income exceeds a threshold: $250,000 for a joint return or a surviving spouse, half that for married filing separately, and $200,000 "in any other case."

The 3.8% figure also matches the payroll side: the hospital insurance tax is 1.45% from the worker and 1.45% from the employer, and the same law added a 0.9% Additional Medicare Tax for high earners, which together come to 3.8%. The label and the rate both say Medicare. The money does not go there, and the next section shows where that is written.

Three taxes say "Medicare." Only two fund it.

Sources: 26 U.S.C. § 3101(b); 26 U.S.C. § 1411; 42 U.S.C. § 1395i(a); 20 CFR § 404.143; IRS NIIT questions and answers. Self-employed people pay the hospital insurance tax under § 1401(b), which § 1395i(a)(2) also credits to the trust fund.

The trust fund statute is short on this point. 42 U.S.C. § 1395i(a) appropriates to the Federal Hospital Insurance Trust Fund "amounts equivalent to 100 per centum of— (1) the taxes imposed by sections 3101(b) and 3111(b) of the Internal Revenue Code of 1986 with respect to wages ... and (2) the taxes imposed by section 1401(b) ... with respect to self-employment income." The 0.9% Additional Medicare Tax is written into § 3101(b)(2), so it is covered. Section 1411 is not mentioned. The 3.8% is collected with your income tax on Form 8960, and nothing in the trust fund's funding sentence sends it to Medicare.

The IRS makes the separation plain in its own guidance: "If you are an individual who is exempt from Medicare taxes, you still may be subject to the Net Investment Income Tax." A tax that applies to people who are outside Medicare's payroll system is not really part of that system.

Paying it earns you nothing from Medicare

This is the part people ask me about. You become eligible for premium-free Part A by working about ten years in jobs that paid Medicare taxes, which Social Security counts as quarters of coverage. 20 CFR § 404.143(a) says Social Security credits a quarter "for each part of the total wages paid and self-employment income credited" in a year. Dividends, rents and capital gains are not wages or self-employment income, so a retiree who pays the 3.8% on a large sale earns no credits from it. It does not lower a Part A premium, does not reduce Part B, and does not offset IRMAA. It is simply an income tax with a Medicare label.

Two different MAGIs, and which income lands where

Both the 3.8% tax and Medicare's income-related premiums use something called modified adjusted gross income, and both start from the same adjusted gross income on your Form 1040. They modify it differently. For the investment income tax, § 1411(d) adds back only the foreign earned income exclusion. For IRMAA, 20 CFR § 418.1010(b)(6) adds tax-exempt interest and a few other items. And the investment income tax has a second test the premium does not: the income has to be investment income before the 3.8% touches it.

Sources: IRS NIIT questions 8–10 and its home-sale answer ("does not apply to any amount of gain that is excluded from gross income"); § 1411(c)(6) for self-employment income; 20 CFR § 418.1010. Rent counts as investment income unless it comes from a real estate business you actively run; your tax preparer decides that line.

Two rows matter most for retirees. First, IRA withdrawals and Social Security are never taxed at 3.8% themselves, because the IRS lists both as income that is not net investment income. But they sit in adjusted gross income, so a large withdrawal can lift a household over $250,000 and expose its dividends and gains to the tax. Second, municipal bond interest is the reverse: invisible to the 3.8% tax, but added back for IRMAA, which we covered in our municipal bond post. The same portfolio can look small to one test and large to the other.

A Fruita rental sale: the "Medicare tax" against the Medicare bill

Take a Mesa County couple with $160,000 of other income in 2026: two pensions, IRA withdrawals and the taxable part of Social Security. They sell a rental house in Fruita they have owned for years, for a long-term gain of $120,000. Their MAGI for 2026 is $280,000.

The investment income tax. The 3.8% applies to the smaller of their net investment income ($120,000) or their MAGI above $250,000 ($30,000). The smaller number is $30,000, so the tax is $1,140. Most of the gain is never touched by it, because most of the gain sits under the line.

The Medicare premium. Social Security reads the 2026 return to set 2028 premiums, under 20 CFR § 418.1135, "the tax year 2 years prior." Using the 2026 tiers as a yardstick, since 2028's have not been published, $280,000 joint is above $274,000, the start of the second tier. That adds $202.90 a month to Part B and $37.50 to Part D, per person. For the couple, that is $240.40 each per month and $5,769.60 for the year.

So the tax called a Medicare contribution costs them $1,140 and none of it goes to Medicare. The surcharge that does go to Medicare costs them about five times as much. The first IRMAA line, $218,000 joint for 2026 and $222,000 for 2027 per the Medicare & You 2027 handbook, also sits $32,000 below the 3.8% line. For a single filer the gap is far wider: IRMAA starts at $109,000, the investment income tax at $200,000. A widow selling the same rental will usually be well into IRMAA before the 3.8% starts. These figures are illustrative, federal only, and leave out depreciation recapture and selling costs. Your tax preparer will have the real numbers.

Still working at 65? The 0.9% is the one that funds Medicare

For a Grand Junction physician, business owner or executive still earning a salary past 65, the tax to watch on paychecks is the 0.9% Additional Medicare Tax, not the 3.8%. It applies to wages and self-employment income over the same $250,000 joint / $200,000 single lines, and it is credited to Medicare's trust fund as part of § 3101(b). The IRS says an employer "must withhold Additional Medicare Tax from wages it pays to an individual in excess of $200,000 in a calendar year, without regard to the individual's filing status," which means a married couple can be over- or under-withheld and settle it on Form 8959. The IRS also says you can owe both taxes in the same year "but not on the same type of income": the 0.9% on the salary, the 3.8% on investment income.

Wages also keep earning Medicare credits, which matters for a spouse whose own record is short. If that applies to you, see our post on getting Medicare at 65 without your own work history.

What I would do

Treat the 3.8% as an income tax question for your tax preparer, and do not expect it to show up anywhere in your Medicare paperwork. Then do the Medicare side separately. Before a large sale, add the gain to your expected income and compare it with the IRMAA lines first, $218,000 joint or $109,000 single for 2026, because that line is lower and the surcharge lasts a full year of premiums. If you are near a line, ask whether the timing of the sale, an installment sale or harvested losses changes which tier you land in. Our posts on capital gains and IRMAA and selling a house go through those choices. And remember that Open Enrollment runs October 15 to December 7: the plan you choose for 2027 is a separate decision from the premium tier your income sets, and both are worth reviewing this fall.

How we know all this: the Medicare On Main Data Desk frames every article with public data — here, 26 U.S.C. Chapter 2A and §§ 1411 and 3101(b), 42 U.S.C. § 1395i(a), and 20 CFR §§ 404.143, 418.1010 and 418.1135, all quoted as published on Cornell LII; the IRS Net Investment Income Tax page and its questions and answers; the IRS Additional Medicare Tax questions and answers; the CMS fact sheet of November 14, 2025 for the 2026 IRMAA tiers; and the Medicare & You 2027 handbook for the first 2027 IRMAA line. The worked example is illustrative, federal only, and uses 2026 IRMAA tiers as a stand-in for 2028. This is education, not tax advice; review any sale, withdrawal or conversion with your tax advisor, and confirm plans, costs and eligibility with a licensed agent or Medicare.gov. We take no payment from any carrier to feature a plan.