Learn what capital gain tax is, when it applies, and why realization timing matters for investors and households.
Capital gain tax is the tax imposed on the profit realized when a capital asset is sold for more than its tax basis or acquisition cost. The key word is realized: the tax usually arises when the gain is crystallized by sale or another taxable disposition.
If an investor buys an asset for one amount and later disposes of it for more, the taxable gain is generally the sale proceeds minus the adjusted basis. Tax systems often distinguish between short-term and long-term gains, different asset classes, or special exemptions, which means the effective tax outcome depends on both the amount of gain and how the gain is characterized.
This matters because taxes change after-tax return, asset-holding decisions, rebalancing behavior, and estate or gift planning. A strong investment result before tax can look very different once realization rules and rates are applied.