Capital Gains for High Earners: The 0% Bracket You’re Missing and the 3.8% Surtax You Didn’t Know You Owed

Long-term capital gains get their own set of gentle tax brackets — 0%, 15%, and 20% — completely separate from the brackets on your wages. But two things trip up high earners: a stealth 3.8% surtax that lifts the real top rate to 23.8%, and the fact that the lowest bracket is a genuine 0% that many people could use and never do. The difference between a short-term and a long-term sale, and the timing of when you realize a gain, can swing your tax bill by tens of percentage points.

Short-term vs. long-term: the single most important line

Hold an asset one year or less and the gain is short-term, taxed at your ordinary income rate — up to 37%. Hold it more than a year and it's long-term, taxed at the preferential rates below. On a large gain, crossing that one-year mark can cut your tax nearly in half. Patience is, quite literally, a tax strategy.

2025 taxable income (MFJ)	Long-term cap-gains rate
Up to $96,700	0%
$96,701 – $600,050	15%
Above $600,050	20%

The stealth surtax: 3.8% NIIT

Here's the rate nobody mentions until you owe it. The Net Investment Income Tax adds 3.8% on top of your capital gains (and dividends, interest, and rental income) once your MAGI exceeds $200,000 single / $250,000 married filing jointly. So the real top rate on long-term gains isn't 20% — it's 23.8%. And like the Medicare surtax, those thresholds were set in 2013 and have never been adjusted for inflation, so they pull in more households every year. Any gain-timing plan for a high earner has to account for the NIIT, not just the headline bracket.

The Aha: the 0% bracket is real — and reachable

Most high earners assume the 0% capital-gains rate is theoretical. It isn't. It applies whenever your taxable income (including the gain) stays under the threshold — and that happens more than you'd think: in early retirement gap years, a sabbatical, a business loss year, or for adult children in low brackets. A retiree with modest income can deliberately realize gains up to the top of the 0% bracket and pay zero federal tax, resetting their cost basis higher for free ("tax-gain harvesting"). Gifting appreciated shares to family members in low brackets, or to charity, multiplies the effect.

A worked 0% harvest

See how reachable the 0% rate really is. The Okafors retired at 63 and live mostly on cash savings, with taxable income around $70,000 — comfortably below the 2025 top of the 0% bracket ($96,700 for joint filers). They hold appreciated index funds with a large unrealized gain. Each December, they deliberately sell enough to realize about $26,000 of long-term gains — filling the gap up to $96,700 — and immediately rebuy the same funds.

The result: they pay $0 in federal tax on that gain, yet their cost basis ratchets up by $26,000, permanently shrinking the taxable gain on a future sale. Repeated across several gap years, this quietly resets a six-figure chunk of embedded gains to a fresh, higher basis — for free. Most high earners assume the 0% bracket is a fantasy; in early retirement it is a recurring, deliberate strategy.

Two more levers worth knowing

• Asset location. Hold tax-inefficient assets (taxable bonds, REITs, actively traded funds) inside IRAs and 401(k)s, and tax-efficient ones (broad index funds, individual stocks you will hold) in taxable accounts. Same portfolio, lower lifetime tax drag — purely from where each piece sits.
• Donate the gain away. Giving appreciated stock directly to charity (or to a donor-advised fund) lets you skip the capital-gains tax entirely and deduct the full market value, versus selling, paying 23.8%, and donating what is left. For the charitably inclined, it is the single most efficient way to give.
• Spread a big sale over time. An installment sale lets you receive the proceeds — and recognize the gain — across several years, which can keep you under the NIIT threshold or out of the 20% bracket in any single year.

Key takeaways

• Holding more than a year converts ordinary rates (up to 37%) into the 0/15/20% long-term rates.
• The 3.8% Net Investment Income Tax lifts the real top rate to 23.8% above $200k/$250k of MAGI.
• The 0% bracket is reachable in low-income years — harvest gains tax-free to reset your basis higher.

Levers that change what you pay

• Hold past one year whenever feasible to convert ordinary rates to capital-gains rates.
• Harvest losses to offset gains dollar-for-dollar (mind the wash-sale rule).
• Time realizations into lower-income years to stay under the 15%, 20%, or NIIT thresholds.
• Donate appreciated stock instead of cash — you skip the gain entirely and may deduct the full value.
• Hold until death where appropriate — heirs get a stepped-up basis and the unrealized gain disappears.

Capital gains are one of the few taxes whose timing you fully control. That control is exactly where the planning value lives.