Executive Summary
Does the 3.8% NIIT apply to my equity compensation?
It depends on the type of income. Wages and ordinary income from RSU vesting or stock option exercises are NOT subject to NIIT. However, capital gains from selling vested shares (RSU, ISO, NSO, or ESPP) ARE subject to NIIT if your MAGI exceeds $200,000 (single) or $250,000 (married filing jointly). The tax is 3.8% on the lesser of your net investment income or the amount your MAGI exceeds the threshold.
The Net Investment Income Tax is a stealth tax that hits equity compensation holders twice—first through ordinary income taxes at vesting or exercise, then through the 3.8% NIIT when they sell shares at a gain. For a senior engineer selling $500,000 of appreciated RSU shares with a $250,000 MAGI, the NIIT alone adds $9,500 to the tax bill. Employees with concentrated stock positions routinely face $15,000–$50,000+ in annual NIIT liability from rebalancing.
The bottom line: The NIIT is a 3.8% surtax under IRC Section 1411 that applies to net investment income—including capital gains from equity compensation sales—when your Modified Adjusted Gross Income exceeds fixed thresholds that have never been adjusted for inflation since 2013. What was designed as a tax on the wealthy now captures a large share of tech workers with vesting equity. Understanding which income triggers NIIT and which is exempt is the first step to keeping thousands in your pocket.1
Critical Warning: The MAGI thresholds for NIIT ($200,000 single / $250,000 MFJ) have been frozen since the tax was enacted in 2013. With inflation and rising tech salaries, employees who never expected to be subject to this surtax are now caught every year. Unlike AMT exemptions, there is no inflation adjustment mechanism for NIIT thresholds—Congress must act to change them.
What Is the Net Investment Income Tax?
The Statutory Framework
The NIIT was enacted as part of the Affordable Care Act (ACA) in 2010 and took effect on January 1, 2013. Codified in IRC Section 1411, it imposes a 3.8% tax on the lesser of:
- Net investment income (NII), or
- The excess of MAGI over the applicable threshold
This surtax is reported on IRS Form 8960 and is in addition to all other federal income taxes, including the 0.9% Additional Medicare Tax on earned income.2
MAGI Thresholds (2025–2026)
Unlike most tax parameters, NIIT thresholds are not indexed for inflation. They have remained unchanged since 2013:
| Filing Status | MAGI Threshold | Unchanged Since |
|---|---|---|
| Single | $200,000 | 2013 |
| Married Filing Jointly (MFJ) | $250,000 | 2013 |
| Married Filing Separately (MFS) | $125,000 | 2013 |
| Head of Household | $200,000 | 2013 |
| Qualifying Surviving Spouse | $250,000 | 2013 |
What Counts as Net Investment Income?
| Included in NII (Subject to NIIT) | Excluded from NII (Exempt from NIIT) |
|---|---|
| Capital gains (short-term and long-term) | Wages, salaries, bonuses |
| Interest income | Self-employment income (active) |
| Dividend income | Distributions from most retirement plans |
| Rental and royalty income (passive) | Social Security benefits |
| Passive activity income | Tax-exempt municipal bond interest |
| Annuity income (non-qualified) | Income from active trade or business |
Source: IRC Section 1411(c)
The Critical Distinction: Earned Income vs. Investment Income in Equity Compensation
Is the ordinary income from RSU vesting subject to NIIT?
No. The ordinary income recognized when RSUs vest is treated as wages/compensation income under IRC Section 1411(c)(6), which is explicitly excluded from net investment income. NIIT only applies when you later sell those vested shares and realize a capital gain. However, your RSU vesting income does increase your MAGI, which can push you above the NIIT threshold and make other investment income subject to the 3.8% tax.
This is the single most important concept for equity compensation holders to understand. The tax treatment depends entirely on what type of income is generated at each stage:
The Two-Stage Tax Model
| Stage | Income Type | Subject to NIIT? | Example |
|---|---|---|---|
| Stage 1: Vesting/Exercise | Ordinary income (wages) | ❌ No | RSU vests at $150/share → $150 × shares is W-2 income |
| Stage 2: Selling shares | Capital gain (investment) | ✅ Yes | Sell those shares at $180/share → $30/share gain is NII |
The trap: while Stage 1 income is exempt from NIIT, it increases your MAGI, making it more likely that your Stage 2 capital gains will be subject to the 3.8% surtax.
Equity Compensation NIIT Matrix
| Equity Type | Event | Income Type | NIIT Subject? | Notes |
|---|---|---|---|---|
| RSU | Vesting | Ordinary income | ❌ No | Wages per IRC §1.1411-1(d) |
| RSU | Sale at gain after vesting | Capital gain | ✅ Yes | Gain above FMV at vesting date |
| ISO | Exercise | No regular income | ❌ No | AMT adjustment only |
| ISO | Qualifying disposition | Long-term capital gain | ✅ Yes | Full spread taxed as LTCG |
| ISO | Disqualifying disposition | Ordinary income + capital gain | Partial | Ordinary portion exempt; capital gain portion subject |
| NSO | Exercise | Ordinary income | ❌ No | Spread is W-2 income |
| NSO | Sale after exercise | Capital gain | ✅ Yes | Gain above FMV at exercise |
| ESPP | Qualifying disposition | Ordinary income + capital gain | Partial | Ordinary portion exempt; capital gain subject |
| ESPP | Disqualifying disposition | Ordinary income + capital gain | Partial | Ordinary portion exempt; capital gain subject |
How NIIT Applies to Each Equity Type
RSU Sales
When RSU shares vest, the full FMV is reported as ordinary income on your W-2. This is not investment income. But when you later sell those shares, any gain above the FMV at vesting becomes a capital gain subject to NIIT.
Example: Senior engineer with RSU sales
| Item | Amount |
|---|---|
| Base salary | $220,000 |
| RSU vesting income (ordinary) | $180,000 |
| Total W-2 income | $400,000 |
| RSU shares sold at gain (capital gain) | $75,000 |
| Dividend and interest income | $15,000 |
| Total MAGI | $490,000 |
| Net investment income | $90,000 |
| MAGI excess over $200K threshold (single) | $290,000 |
| NIIT base (lesser of $90K NII or $290K excess) | $90,000 |
| NIIT owed (3.8% × $90,000) | $3,420 |
The RSU vesting income ($180,000) is exempt from NIIT but pushes MAGI well above the threshold, ensuring all $90,000 of investment income is fully subject to the 3.8% surtax.
ISO Qualifying vs. Disqualifying Dispositions
The NIIT treatment of ISOs varies dramatically based on whether you achieve a qualifying disposition. For background on the AMT implications of ISO exercises, see our dedicated guide.
Qualifying disposition (held ≥ 2 years from grant, ≥ 1 year from exercise): The entire gain is long-term capital gain—fully subject to NIIT.
Disqualifying disposition (sold before meeting holding periods): The bargain element is recharacterized as ordinary income (exempt from NIIT), but any additional appreciation is capital gain (subject to NIIT).
| Disposition Type | Ordinary Income (Exempt) | Capital Gain (NIIT Subject) | Total NIIT Impact |
|---|---|---|---|
| Qualifying (exercise at $10, sell at $80) | $0 | $70/share LTCG | 3.8% × $70/share |
| Disqualifying (exercise at $10, FMV $50, sell at $80) | $40/share (bargain element) | $30/share STCG | 3.8% × $30/share |
Key Insight: A disqualifying disposition actually produces less NIIT liability because a larger portion of the gain is classified as ordinary income (exempt from NIIT). However, the ordinary income portion is taxed at higher ordinary rates (up to 37%), so the total tax bill is typically higher. Use the capital gains calculator to model both scenarios.
NSO Post-Exercise Sales
When you exercise NSOs, the spread (FMV minus exercise price) is ordinary income on your W-2—exempt from NIIT. If you hold the shares and sell later at a higher price, the additional gain is capital gain subject to NIIT.
Example: NSO exercise and hold
| Event | Income Type | Amount | NIIT? |
|---|---|---|---|
| Exercise 5,000 NSOs (strike $20, FMV $60) | Ordinary income | $200,000 | ❌ No |
| Sell 5,000 shares 14 months later at $85 | LTCG | $125,000 | ✅ Yes |
| NIIT on sale (if above threshold) | $4,750 | 3.8% × $125K |
ESPP Sales
ESPP taxation follows a similar split. The discount portion recognized as ordinary income on your W-2 is exempt from NIIT. Capital gains above the purchase price (adjusted for ordinary income) are subject to NIIT.
Calculating Your NIIT Liability
Step-by-Step Calculation (Form 8960)
The NIIT calculation follows a straightforward formula, but the inputs require careful categorization:
Step 1: Calculate your MAGI (generally the same as AGI for most W-2 employees)
Step 2: Determine your net investment income:
| NII Component | Your Amount |
|---|---|
| Capital gains from equity sales | $ _____ |
| Interest income | $ _____ |
| Dividend income | $ _____ |
| Rental/passive income | $ _____ |
| Less: investment expenses | ($ _____) |
| Total Net Investment Income | $ _____ |
Step 3: Calculate NIIT
NIIT = 3.8% × min(Net Investment Income, MAGI − Threshold)
Comprehensive Example: Dual-Income Tech Couple
| Income Item | Taxpayer A | Taxpayer B | Joint Total |
|---|---|---|---|
| Base salary | $250,000 | $180,000 | $430,000 |
| RSU vesting income | $320,000 | $0 | $320,000 |
| RSU sale capital gains | $95,000 | $0 | $95,000 |
| ESPP qualifying disposition LTCG | $18,000 | $0 | $18,000 |
| ESPP ordinary income (discount) | $7,500 | $0 | $7,500 |
| Dividend income | $12,000 | $8,000 | $20,000 |
| Interest income | $5,000 | $3,000 | $8,000 |
| MAGI | $898,500 | ||
| Net Investment Income | $141,000 |
| Calculation | Amount |
|---|---|
| MAGI | $898,500 |
| MFJ threshold | $250,000 |
| MAGI excess | $648,500 |
| Net investment income | $141,000 |
| NIIT base (lesser of $141K or $648.5K) | $141,000 |
| NIIT owed (3.8% × $141,000) | $5,358 |
Note: The $320,000 in RSU vesting income and $7,500 in ESPP ordinary income are excluded from NII but inflate MAGI, guaranteeing that 100% of the couple's investment income is subject to NIIT.3
The Bracket Creep Problem
Because the NIIT thresholds have been frozen since 2013, inflation steadily drags more taxpayers above the line:
| Year | $200K Threshold in 2013 Dollars | Approx. % of Tech Workers Above |
|---|---|---|
| 2013 | $200,000 | ~15% |
| 2018 | $176,000 | ~22% |
| 2023 | $152,000 | ~35% |
| 2026 | ~$138,000 | ~42% |
A salary of $200,000 in 2013 is equivalent to roughly $275,000 in 2026 purchasing power—yet the threshold remains $200,000.4
Strategies to Minimize NIIT Exposure
What is the best way to reduce NIIT on equity compensation?
The most effective strategy is to spread equity sales across multiple tax years to keep net investment income low in each year. Additional tactics include donating appreciated shares to charity (eliminates the capital gain entirely), tax-loss harvesting to offset gains, maximizing pre-tax retirement contributions to reduce MAGI, and using specific lot identification to sell highest-basis shares first.
1. Time Your Equity Sales Strategically
Spreading sales across tax years can keep MAGI below thresholds or reduce the overlap between NII and excess MAGI:
| Strategy | How It Reduces NIIT | Best For |
|---|---|---|
| Sell in low-income years | Lower MAGI → less NIIT exposure | Job transitions, sabbaticals, early retirement |
| Spread sales across years | Keep NII below MAGI excess in each year | Large concentrated positions |
| Sell before RSU vesting dates | Avoid MAGI spike from vesting + sale in same year | Employees with predictable vesting schedules |
| Use specific lot identification | Sell highest-basis lots first to minimize capital gains | Multiple RSU vesting tranches |
2. Charitable Giving with Appreciated Shares
Donating appreciated equity compensation shares to a qualified charity eliminates the capital gain entirely—removing it from both regular capital gains tax and NIIT:
- Donate shares held > 1 year for full FMV deduction
- No capital gain recognized = no NIIT on donated shares
- Deduction limited to 30% of AGI for appreciated property (5-year carryforward available)
- See our guide on donating equity shares for the full strategy
3. Installment Sales (for Private Company Shares)
For private company shares (e.g., tender offers or secondary sales), an installment sale under IRC Section 453 spreads gain recognition across multiple years, potentially keeping MAGI below the NIIT threshold in each year.
4. Tax-Loss Harvesting
Realizing capital losses offsets capital gains dollar-for-dollar, directly reducing net investment income. See our tax-loss harvesting guide for equity-specific strategies. Use the capital gains calculator to model the impact before executing trades.
5. Maximize Retirement Plan Contributions
Contributions to 401(k), traditional IRA, and HSA accounts reduce MAGI. For high earners near the NIIT threshold, maximizing these deductions can push MAGI below $200,000/$250,000:
| Account | 2026 Contribution Limit | MAGI Reduction |
|---|---|---|
| 401(k) employee | $24,000 | Direct |
| 401(k) catch-up (age 50+) | $7,500 | Direct |
| Traditional IRA (if deductible) | $7,000 | Direct |
| HSA (family) | $8,550 | Direct |
6. Consider ISO Disqualifying Dispositions
As shown above, a disqualifying disposition converts more of the ISO gain into ordinary income (exempt from NIIT). While this means higher ordinary tax rates, the combined tax bill may be lower than a qualifying disposition when NIIT and state taxes are factored in. The break-even depends on your marginal ordinary rate, state tax rate, and MAGI level.
NIIT Interaction with Other Taxes
The Full Federal Tax Stack on Equity Sales
| Tax | Rate | Applies To | Equity Impact |
|---|---|---|---|
| Ordinary income tax | 10–37% | RSU vesting, NSO exercise, ISO disqualifying | Vesting/exercise income |
| Long-term capital gains | 0/15/20% | Sales held > 1 year | Post-vesting/exercise appreciation |
| Short-term capital gains | 10–37% | Sales held ≤ 1 year | Same-day or quick sales |
| NIIT | 3.8% | NII when MAGI > threshold | Capital gains from equity sales |
| Additional Medicare Tax | 0.9% | Wages > $200K/$250K | RSU vesting, NSO exercise |
| AMT | 26/28% | ISO bargain element | ISO exercises |
For a high-earning tech employee selling appreciated ISO shares in a qualifying disposition, the maximum combined federal rate is 23.8% (20% LTCG + 3.8% NIIT). Add state taxes (e.g., 13.3% in California), and the effective rate can exceed 37%—approaching ordinary income rates. For state-specific planning, see our California tax guide.5
Frequently Asked Questions
Does RSU vesting income trigger the 3.8% NIIT?
No. RSU vesting income is classified as wages/compensation under IRC Section 1411(c)(6) and is explicitly excluded from net investment income. However, it counts toward your MAGI, which determines whether your other investment income is subject to NIIT. A large RSU vesting event can push your MAGI above the threshold, subjecting all of your capital gains, dividends, and interest to the 3.8% surtax.
Source: Treasury Regulation § 1.1411-1(d)
Are ESPP shares subject to NIIT when I sell them?
Yes, partially. The ordinary income portion (discount recognized on your W-2) is exempt from NIIT. The capital gain portion—whether short-term or long-term—is net investment income subject to NIIT if your MAGI exceeds the threshold. For qualifying dispositions, the ordinary income is limited to the lesser of the actual discount or the actual gain, with the remainder taxed as capital gains subject to NIIT.
Can I avoid NIIT by doing a same-day sale of my RSUs?
A same-day sale at vesting means there is minimal or no capital gain (only the spread between vesting price and sale price, which is typically negligible). This effectively avoids NIIT on the equity income because virtually all the income is classified as ordinary wages. However, you forfeit any future appreciation potential and lose the ability to benefit from long-term capital gains rates.
Does the 3.8% NIIT apply to my 401(k) distributions?
No. Distributions from tax-qualified retirement plans—including 401(k), 403(b), traditional IRA, and Roth IRA—are excluded from net investment income under IRC Section 1411(c)(5). This is true even if the distribution is taxable as ordinary income.
Source: IRC Section 1411(c)(5)
Will Congress ever adjust the NIIT thresholds for inflation?
As of March 2026, there is no enacted legislation to index NIIT thresholds. Various proposals have been introduced—some to increase thresholds, others to expand NIIT to cover all income above the threshold (not just investment income). The thresholds have been frozen at $200,000/$250,000 since 2013, and bracket creep continues to expand the tax's reach annually.
How do I report NIIT on my tax return?
NIIT is calculated on IRS Form 8960 (Net Investment Income Tax—Individuals, Estates, and Trusts) and reported on Schedule 2, line 18 of Form 1040. You must file Form 8960 if your MAGI exceeds the threshold, even if your net investment income is zero.
Source: IRS Form 8960 Instructions
Footnotes
Disclaimer: This guide discusses legal tax optimization strategies only. Tax evasion is illegal and is never recommended. This content is for educational purposes and does not constitute tax, legal, or financial advice. Tax laws vary by jurisdiction and change frequently. Always consult a qualified tax professional before making decisions based on this information. The authors accept no liability for actions taken based on this content.
Primary Sources
| Source | Type | URL |
|---|---|---|
| IRC Section 1411 | Statute | law.cornell.edu/uscode/text/26/1411 |
| Treasury Reg. § 1.1411-1 through 1.1411-10 | Regulation | law.cornell.edu/cfr/text/26/1.1411-1 |
| IRS Form 8960 Instructions | Official Guidance | irs.gov/pub/irs-pdf/i8960.pdf |
| IRS Publication 550 | Official Guidance | irs.gov/publications/p550 |
| IRS Publication 525 | Official Guidance | irs.gov/publications/p525 |
Last Updated: March 2026 | Research Team: VestingStrategy
Footnotes
-
IRC Section 1411 was enacted as part of the Health Care and Education Reconciliation Act of 2010 (P.L. 111-152), effective January 1, 2013. The 3.8% rate matches the combined employee and employer Medicare Hospital Insurance tax rate. ↩
-
The 0.9% Additional Medicare Tax (IRC Section 3101(b)(2)) applies to wages above $200,000/$250,000, while NIIT applies to investment income above the same thresholds. Together, these ACA taxes add 4.7% in surtaxes for high-earning employees with investment income. ↩
-
Treasury Regulation § 1.1411-8 provides that net investment income does not include any item taken into account in determining self-employment income subject to SECA tax. Similarly, § 1.1411-1(d) excludes wages subject to FICA from NII. ↩
-
CPI-U data from the Bureau of Labor Statistics shows cumulative inflation of approximately 38% from January 2013 to January 2026. The $200,000 threshold in 2013 dollars is equivalent to approximately $276,000 in 2026 dollars. ↩
-
The maximum combined federal rate on long-term capital gains is 20% + 3.8% NIIT = 23.8%. California's top rate of 13.3% applies to all capital gains as ordinary income, producing a combined federal + state rate of approximately 37.1%. ↩