Short-Term vs Long-Term Capital Gains: The One-Year Holding Period

The difference between short-term and long-term capital gains is a single rule: if you hold an asset for more than one year before selling, the gain qualifies for preferential tax rates (0%, 15%, or 20%); if you sell within one year, the gain is taxed at your ordinary income rate (up to 37%). That one-year clock starts on your purchase date and follows specific day-count rules that trip up many traders.

The One-Year Cliff

The holding period is binary: either an asset is held more than one year (long-term) or it is not (short-term). There is no middle ground, no escalating benefit for holding 6 months vs. 11 months.

If you buy a stock on March 15, 2024, at $100, the one-year anniversary is March 14, 2025. If you sell on March 14 at $150, the gain is short-term; if you sell on March 15, it is long-term.

That $50 gain can be taxed at 37% (short-term) or 15% (long-term), depending on which side of the line you fall. The tax owed is $18.50 or $7.50—a difference of $11. Across a portfolio, this difference is often thousands of dollars.

Exact Day-Count Rules

The IRS counts calendar days, not trading days. Weekends and holidays are included.

Start date (acquisition): The day you purchased the asset or exercise date for options. For stock purchased on the open market, this is the trade date, not the settlement date (which is typically T+2).

End date (sale): The day you sold the asset. Again, this is the trade date, not the settlement date.

One year equals 365 days: On the 366th day, you are past the one-year mark. Selling on day 365 is short-term; selling on day 366 is long-term.

Year-end complications: If you buy on December 31, 2024, the one-year anniversary is December 30, 2025 (day 365). You cannot sell until December 31, 2025 to be long-term. This asymmetry—having to sell a day after the calendar-year anniversary—catches many traders off guard.

Examples and Edge Cases

Leap year holding periods: If you buy on February 29, 2024, and hold through to February 28, 2025, you’ve held 365 days. Selling on February 29, 2025 (day 366 of a non-leap year) makes it long-term.

Buying and selling on the same day: Short-term. You have not held for more than one day.

Buying, then the stock goes ex-dividend, then selling: For dividend purposes, you must hold through the ex-dividend date to receive the dividend. But the ex-dividend date is not the holding period date. The holding period starts on the trade date of purchase and ends on the trade date of sale, regardless of dividend dates. The same one-year rule applies.

Inherited stock: If you inherit stock, your holding period is deemed long-term regardless of how long the deceased held it. The cost basis is also “stepped up” to fair market value on the date of death. This is a significant tax break and is why inheriting assets is often more tax-efficient than gifting them during life.

Stock split or dividend reinvestment: A stock split or a stock dividend does not affect the holding period of the original shares. If you buy 100 shares and the company does a 2-for-1 split giving you 200 shares, your holding period for the 200 shares is the same as for the original 100. Dividends reinvested automatically also carry the original purchase date.

Employee stock options: The holding period for exercised options often uses the grant date as the start date, not the exercise date. This is an exception to the normal rule and applies to incentive stock options (ISOs). Nonqualified stock options (NSOs) use the exercise date. This distinction is critical for calculating whether an ISO sale qualifies for favorable treatment under Section 422.

The Tax Rate Impact

The shift from short-term to long-term cuts the tax rate dramatically for most filers.

A trader in the 24% tax bracket with a $10,000 short-term gain owes $2,400. The same $10,000 as a long-term gain is taxed at 15%, equaling $1,500—a savings of $900, or 37.5%.

A high-income filer in the 37% bracket with a $100,000 short-term gain owes $37,000. At the long-term rate of 20%, the same gain yields $20,000 tax—a savings of $17,000.

This is why traders obsess over the one-year mark and why tax planning often includes deferring sales until the clock runs down.

Why the Holding Period Exists

Congress set the one-year threshold to encourage long-term investing and discourage short-term speculation. The preferential long-term rate makes buy-and-hold strategies more tax-efficient than active trading.

Stocks held one year or longer have already contributed to sustained economic growth and capital formation. Short-term traders, by contrast, generate transaction volume and may contribute to volatility. The tax code nudges behavior toward long-term ownership.

Common Mistakes and Traps

Forgetting the trade date. Many traders confuse the settlement date (T+2 for stocks) with the purchase date. The holding period starts on the trade date, not settlement.

Selling too early by a day. A trader buys on March 15, 2024, and intends to sell long-term. But they accidentally sell on March 14, 2025, thinking they’ve held a full year. They are one day short.

Wash-sale confusion. If you realize a loss on a sale and repurchase the same or a substantially identical stock within 30 days (before or after), the loss is disallowed. But many traders forget that the disallowed loss is added to the basis of the new purchase, deferring the tax benefit. The holding period for the new purchase starts fresh, and you must wait another year for long-term treatment on the new lot.

Assuming account transfers reset the clock. Moving shares from a brokerage account to another brokerage or to a retirement account does not restart the holding period. The original purchase date is carried forward.

Mixing up different share lots. If you buy the same stock multiple times and sell a portion, you must track which lot you’re selling. If you buy at $100, then at $150, and later sell at $200, using FIFO (first-in-first-out) you would sell the $100 lot first, and the holding period for that lot determines the tax rate, not the newer purchase.

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