Capital Gains Tax

Every time you sell an investment for more than you paid for it, you owe capital gains tax. It's one of the most common taxes investors face, and understanding how it works can dramatically affect your after-tax returns. The difference between short-term and long-term capital gains tax rates can mean paying 37% versus 0% on the same profit. That's not a rounding error — it's the difference between keeping your gains and giving a third of them to the government.

Short-Term vs Long-Term

The tax rate on your investment gains depends on one thing: how long you held the investment before selling.

Short-term capital gains apply to investments held one year or less. These gains are taxed at your ordinary income tax rate — the same rate you pay on your salary. For a high earner, that can be 32% or even 37%. Frequent trading, day trading, and selling positions within a year all trigger short-term rates.

Long-term capital gains apply to investments held more than one year. These are taxed at preferential rates: 0%, 15%, or 20%, depending on your income. For most Americans, the rate is 15%. For lower-income individuals (taxable income under ~$47,000 single or ~$94,000 married), the rate is actually 0% — you pay no tax on long-term gains.

2025 long-term capital gains rates:

• 0% rate: Taxable income up to ~$47,000 (single) / ~$94,000 (married)
• 15% rate: Taxable income up to ~$518,900 (single) / ~$583,750 (married)
• 20% rate: Taxable income above those thresholds

High earners may also owe the 3.8% Net Investment Income Tax (NIIT) on top of these rates, bringing the effective maximum to 23.8%.

How Cost Basis Works

Your "cost basis" is what you paid for an investment, including commissions. Your capital gain is the selling price minus the cost basis.

Buy 100 shares of XYZ at $50 = $5,000 cost basis. Sell at $80 = $8,000. Your capital gain is $3,000. If you held for over a year, you pay 15% (assuming you're in the middle bracket) = $450 in tax. If you held for less than a year and you're in the 24% bracket, you pay $720. Same gain, different holding period, $270 difference on a single trade.

Specific identification: When you've bought shares at different prices, you can choose which shares to sell (called "specific identification"). Selling the highest-cost shares first minimizes your taxable gain. Your brokerage can track this for you.

Tax-Smart Strategies

Hold for at least one year. This is the simplest and most impactful strategy. Moving from short-term to long-term rates can cut your tax bill by more than half. Before selling any profitable position, check when you bought it. Waiting an extra few weeks to cross the one-year threshold can save significant money.

Use the 0% bracket. In retirement or years with low income, you may be in the 0% long-term capital gains bracket. You can intentionally sell appreciated investments, pay zero tax, and immediately rebuy them — resetting your cost basis higher. This is called "tax gain harvesting" and it's the inverse of tax-loss harvesting.

Harvest losses to offset gains. Capital losses offset capital gains dollar-for-dollar. If you have $10,000 in gains and $10,000 in losses, your net gain is zero — no tax owed. Excess losses can offset up to $3,000 of ordinary income per year, with unlimited carryforward.

Donate appreciated assets. If you donate stock that has appreciated to a qualified charity, you get a tax deduction for the full market value and pay zero capital gains tax. If a stock has gone from $10,000 to $30,000, donating it gives you a $30,000 deduction and eliminates $20,000 in capital gains.

Step-up in basis at death. When you die, your heirs receive your investments with a "stepped-up" cost basis equal to the market value at date of death. All unrealized capital gains are wiped out. This is one of the most powerful tax provisions in the code and a reason to hold appreciated assets rather than selling and gifting cash.

Common Mistakes

Selling winners too early. Panic selling or taking profits before the one-year mark costs you the preferential long-term rate.

Ignoring wash-sale rules. If you sell a stock at a loss and buy it back within 30 days, the loss is disallowed. You must wait 31 days or buy a similar but not "substantially identical" investment.

Not tracking cost basis. If you can't prove your cost basis, the IRS may assume it was zero — meaning your entire sale price is taxable. Keep records.

Overtading. Every trade in a taxable account is a potential tax event. The more you trade, the more taxes you generate. Buy and hold isn't just a good investment strategy — it's a good tax strategy.