Yes, selling shares of stock that have appreciated in value generally triggers a taxable event known as capital gains tax, depending on your tax jurisdiction and the type of account holding the securities. If you hold the shares in a standard taxable brokerage account, profits realized from selling an asset held for one year or less are classified as short-term capital gains and taxed at ordinary income tax rates, whereas assets held for longer than one year qualify for preferential long-term capital gains tax rates. Conversely, selling shares within tax-advantaged retirement accounts like a traditional IRA or 401(k) typically defers tax obligations until withdrawal, while Roth accounts may allow tax-free growth entirely.