The increments to which securities prices are rounded up or rounded down.
The smallest possible change in price to a security. Various regulations exist regarding what the minimum tick is for different securities, and which trades may occur on a tick. For example, until 2007, a short sale could not occur at the same price as the security's previous trade, when that price was itself a downtick from the trade before that. A minimum tick is also called a trading variation. See also: Tick test.
See minimum tick.