A tick is a measure of the minimum upward or downward movement of a security. It is limited by the smallest unit of currency local to the exchange where they are traded.

For example, since 2001, when the Securities and Exchange Commission (SEC) required all stock markets to convert to decimals, the minimum tick size for stocks trading above $1 has been one cent.

Stocks generally trade in one-cent tick increments, while currencies have tick sizes in pips and rates in basis points (bps). Analysts and traders describe any price changes with ticks.