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Sell It All Now, or Over Several Years?
Compare the estimated tax cost of realizing a large stock gain in one year versus spreading it out, using 2026 federal figures. A tax comparison only.
Concentrated Stock Tax Calculator
How This Calculator Works
The Model
This calculator compares the estimated tax cost of realizing the same gain in one tax year versus spreading it evenly across several tax years. Long-term gains stack on top of your other income, so a large one-year gain can push more of it into the 20% federal bracket and above the Net Investment Income Tax threshold. Spreading the gain can keep more of it in lower brackets.
Key Calculations
- Gain: position value − cost basis
- Federal tax: 2026 brackets; long-term gains taxed at 0%/15%/20% stacked above ordinary taxable income (short-term gains at ordinary rates)
- NIIT: 3.8% on the lesser of the gain or modified AGI above $200,000 (single) / $250,000 (joint)
- State: your entered flat rate × the gain
- Spread: the same calculation on gain ÷ years, repeated each year
What it holds constant
- The share price, your other income, and 2026 tax tables are held constant in every year
- It does not project stock prices or returns, and it ignores the market risk of holding the unsold shares
- It ignores the time value of deferring tax, other investment income, credits, itemized deductions, and AMT
- State tax uses a single flat rate; most states have graduated brackets and some tax gains differently
Estimated tax: $578,505 if sold this year, $543,915 if spread over 3 years.
Estimated tax on a $1,800,000 long-term gain
Sell all in 2026
$578,505
32.1% of the gain
Spread over 3 years
$543,915
30.2% of the gain
Estimated tax difference
$34,590
Lower total tax when spread, before price changes
| Scenario | Gain | Federal | NIIT | State | Total |
|---|---|---|---|---|---|
| All in 2026 | $1,800,000 | $342,705 | $68,400 | $167,400 | $578,505 |
| Spread: year 1 | $600,000 | $102,705 | $22,800 | $55,800 | $181,305 |
| Spread: year 2 | $600,000 | $102,705 | $22,800 | $55,800 | $181,305 |
| Spread: year 3 | $600,000 | $102,705 | $22,800 | $55,800 | $181,305 |
| Spread: total | $1,800,000 | $308,115 | $68,400 | $167,400 | $543,915 |
Hypothetical, illustrative tax-cost estimate using 2026 federal figures held constant for every year. It does not project stock prices or investment returns, and it ignores the market risk of holding, other investment income, credits, itemized deductions, AMT, state-specific rules, and future tax-law changes. The NIIT estimate treats AGI as modified AGI. This is not tax, legal, or investment advice; consult your CPA or tax advisor. It should not be used, on its own, to decide whether to buy, sell, or hold any security. Calculations run in your browser; nothing you enter is sent or stored.
All computation happens in your browser. No data leaves your device.
Common questions
Can spreading stock sales over several years lower the total capital gains tax?
What does this comparison leave out?
Are there alternatives to selling a concentrated position outright?
This calculator is provided for educational purposes only and its results are hypothetical and illustrative. It compares estimated tax cost only, holds the share price constant, and does not project prices or returns or reflect the market risk of holding a concentrated position. It does not constitute tax, legal, or personalized investment advice. Consult your CPA or tax advisor before acting. It should not be used, on its own, to decide whether to buy, sell, or hold any security. Calculations run in your browser; nothing you enter is sent or stored.
Brought to you by Rubric Advisors
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Managing a Concentrated Stock Position: Ways to Diversify and What Each Costs
Reducing a large single-stock position usually combines staged sales, 10b5-1 plans, exchanges, and gifts over several years, each with its own trade-offs.
Section 351 ETF Conversions: Exchanging Appreciated Stock for ETF Shares
A Section 351 exchange moves a diversified basket of appreciated securities into a newly launched ETF for its shares, deferring capital gains tax, though September 2026 IRS guidance treats some versions as taxable.
Capital Gains Tax Rates for 2026: Brackets, NIIT, and Netting Rules
In 2026, long-term gains are taxed at 0% up to $49,450 single ($98,900 joint), 15% up to $545,500 ($613,700), and 20% above, plus possible NIIT.
Net Investment Income Tax (3.8%) and the 0.9% Additional Medicare Tax
The 3.8% NIIT hits investment income above $200,000 single or $250,000 joint MAGI; the 0.9% Medicare tax hits wages above the same levels.
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