Capital Gains Tax

Capital gains tax is a tax on the profit made from selling an asset — a stock, a bond, a piece of property — for more than what was originally paid for it. The capital gainis simply the sale price minus the original purchase price (the "cost basis"); tax is owed only on that gain, not on the full sale price.

Many tax systems also distinguish between short-term gains (from assets held for a short period, often under a year) and long-term gains (held longer), usually taxing short-term gains at the same rates as ordinary income and long-term gains at a lower rate.

Income from working a job and profit from selling an investment are both real increases in what someone can spend — in that sense, taxing both makes sense under the same basic logic as any income tax (see Taxable Income): a gain is a genuine increase in someone's ability to pay tax, whether it came from a paycheck or from an investment. So most tax systems apply some tax to capital gains, just as they do to wages.

But capital gains differ from wages in a way that shapes how they're often taxed: a gain isn't realized gradually like a salary — it can build up silently for years as an asset's value rises, then get taxed all at once in the single year it's sold, even though the increase in value happened little by little over a much longer stretch. Many systems tax gains on assets held for longer at a lower rate than gains on assets held briefly, partly to avoid discouraging people from holding productive investments for the long run just to sidestep a tax bill, and partly because a gain that built up over many years, taxed as if it were a single year's ordinary income, could otherwise push someone into a much higher marginal bracket than their situation really reflects.

This creates a real incentive that shapes investor behavior: because long-term gains are usually taxed at a lower rate than short-term gains, investors often have a reason to hold an appreciating asset past the long-term threshold rather than sell it early, purely because of the tax difference — a decision driven by the tax rules, not necessarily by what's best for the investment itself.

Someone buys $5,000 of stock, which grows to $8,000 — a capital gain of $3,000.

Sold after 8 months (short-term):
  Taxed at ordinary income rate (24%) → tax owed: $720

Sold after 14 months (long-term):
  Taxed at lower long-term rate (15%) → tax owed: $450

Same $3,000 gain, same investment — the only difference is how long it was held before selling, and that alone changes the tax bill by $270.