Tick

What Is a Tick?

A tick is a unit of measurement for price changes in financial markets. The word has two common meanings. The first is the minimum price increment, often called tick size, that a security is allowed to move by. The second is an individual price change, as in "the stock ticked up." Both meanings describe the smallest steps prices take.

Tick size is set by exchanges and regulators, and it varies by market. For many US-listed stocks, the tick is one cent, so a share can trade at $50.01 or $50.02 but not at $50.005. Futures contracts have their own tick sizes, usually defined as a number of index points or a fraction of the underlying unit, and each tick is worth a fixed dollar amount.

How Ticks Are Used

Tick size affects the bid-ask spread. A wider minimum increment can make it more expensive to trade in and out of a position, while smaller ticks generally allow tighter spreads and finer price competition between buyers and sellers.

The term also describes tick-level data, a record of every trade and quote as it happens. This differs from price bars, which summarize prices over a set time period. Tick data shows the sequence of trades in fine detail and is often used in market microstructure research and short-term analysis.

Some older rules were built around ticks. Short-sale rules have at times restricted selling a stock unless its most recent price change was upward, a constraint known as an uptick rule. Rules like these have been modified and reintroduced over the years, so their current status should be checked against regulator guidance.

Why It Matters to Investors

For long-term investors, a tick is usually a small detail. Its effect shows up mainly in trading costs and in how precisely orders fill. A limit order priced at a level that is not a valid tick may be rejected by the exchange, so understanding tick size helps explain why an order is priced the way it is.

Ticks also show that prices move in discrete steps rather than continuously. The combined effect of many small ticks on a stock's return is what ultimately matters over time.