Capital Gains Tax

Capital gains tax is one of the most significant tax considerations for investors in the United States. When you sell a capital asset for more than you paid for it, the difference — known as the capital gain — becomes taxable income in the year the sale occurs. The IRS distinguishes between two types of capital gains based on how long you held the asset before selling it: short-term and long-term.

Short-term capital gains apply to assets held for one year or less and are taxed at ordinary income tax rates, which can be as high as 37% for the highest earners in 2025. Long-term capital gains, which apply to assets held for more than one year, benefit from preferential tax rates of 0%, 15%, or 20%, depending on your taxable income and filing status.

For 2025, the 0% long-term capital gains rate applies to single filers with taxable income up to $48,350 and married filing jointly couples with income up to $96,700. The 15% rate applies to single filers earning between $48,351 and $533,400, and the 20% rate kicks in above those thresholds. High-income taxpayers may also owe the 3.8% Net Investment Income Tax on top of these rates.

Capital gains are reported on Schedule D of Form 1040, with the details of each transaction listed on Form 8949. Losses from capital asset sales can offset capital gains, and if losses exceed gains, up to $3,000 of the excess loss can be deducted against ordinary income each year, with the remainder carried forward to future tax years.

Strategic planning around capital gains tax — such as timing asset sales, tax-loss harvesting, and utilizing tax-advantaged accounts — can meaningfully reduce your overall tax burden. Understanding how capital gains tax works is foundational to building a tax-efficient investment portfolio.

Short-Term vs Long-Term Comparison: The rate differential between short-term and long-term treatment is the single most controllable variable in capital gains taxation. An investor in the 32% ordinary income bracket who holds a position just long enough to qualify for long-term treatment effectively cuts the federal rate on that gain to 15% — a 17-percentage-point saving on every dollar of profit. On a $50,000 gain, that is $8,500 in federal taxes preserved simply by waiting a few extra months. The calculus does not always favor waiting — if a position has deteriorated or the investment thesis has changed, it may be rational to sell short-term and absorb the higher tax rate — but the break-even analysis should always be performed before acting.

State-Level Variation: Federal capital gains tax is only part of the picture. Most states tax capital gains as ordinary income and provide no preferential rate for long-term gains. California, for example, taxes all capital gains at ordinary state income rates that can reach 13.3%, producing a combined federal and state marginal rate exceeding 36% on long-term gains for high earners — and above 50% for short-term gains. A handful of states, including Florida, Texas, and Nevada, impose no personal income tax at all, making them attractive domiciles for investors planning large liquidity events. Consult a tax professional to understand how your state treats capital gains before planning a major sale.

Planning Considerations: Effective capital gains tax planning extends well beyond simply holding assets for more than one year. Strategies include harvesting losses to offset gains, making charitable gifts of appreciated shares (which allows you to deduct the full fair market value while avoiding the capital gains tax on the appreciation), converting traditional IRA assets in low-income years to reduce future required minimum distributions, and spreading large gains across multiple tax years where possible. Investors approaching retirement should also map out how capital gains interact with Medicare premium surcharges (IRMAA), Social Security taxability thresholds, and the phase-out of various deductions. Consult a tax professional before implementing any multi-year tax plan to ensure it accounts for your full financial picture.

Netting Rules: The IRS requires capital gains and losses to be netted in a specific order before any tax is calculated. First, all short-term gains and losses are combined to produce a net short-term gain or loss. Second, all long-term gains and losses are combined to produce a net long-term gain or loss. Third, if the two results have opposite signs — one a gain, the other a loss — they are offset against each other. The final net figure determines the tax treatment. A net short-term gain is taxed at ordinary income rates. A net long-term gain is taxed at the preferential 0/15/20% rates. A net capital loss of any kind reduces ordinary income by up to $3,000 per year, with the remainder carried forward. Understanding the netting sequence prevents investors from assuming that a short-term loss automatically offsets a long-term gain dollar for dollar at the same rate.

State-by-State Comparison: Capital gains taxation varies substantially by state, making state domicile a meaningful financial planning variable for investors with large realized gains. California applies its top income tax rate of 13.3% to all capital gains — there is no preferential long-term rate at the state level, and the combined federal plus state rate on long-term gains can exceed 36.8% for high earners (23.8% federal including NIIT plus 13%). New York taxes capital gains as ordinary income at rates up to 10.9% for high earners at the state level, plus New York City tax adding up to 3.876%. By contrast, Florida, Texas, Nevada, Wyoming, South Dakota, and Washington (for most income) impose no personal income tax, making them popular relocation destinations for investors planning major liquidity events. Nine states have a flat tax rate that applies to all income including capital gains. Hawaii, Oregon, and Minnesota have effective top rates on capital gains that, when combined with federal rates, put them in the highest combined burden tier nationally. Accurate tracking of holding periods across all taxable accounts is therefore an essential element of tax-efficient portfolio management for U.S. investors. Tax-loss harvesting — selling positions at a loss to offset realized capital gains elsewhere in the portfolio — is a widely used strategy for managing capital gains tax liability in taxable brokerage accounts, and it can generate meaningful after-tax return improvements over time when implemented systematically.