Glossary
Tick size
The smallest price increment in which a security can be quoted or traded; for most US stocks, one cent per share as of 2026.
On this page
Tick size is the minimum amount by which a price can change when a security is quoted. In US stocks priced at $1.00 or more, displayed quotes move in whole cents, so the smallest possible bid-ask spread is $0.01. Tick size matters because it puts a floor under trading costs, shapes how much liquidity sits at each price, and influences how orders are queued and routed.
How it works in the US
Regulation NMS Rule 612 sets the minimum quoting increment. As of 2026, stocks quoted at $1.00 or above use $0.01 ticks, and stocks quoted below $1.00 may be quoted in increments of $0.0001. Trades can still print at finer prices, for example when an off-exchange market maker gives price improvement of a fraction of a cent.
In 2024 the SEC amended the rule to create a half-penny ($0.005) tick for heavily traded stocks whose average quoted spread is a cent or close to it. Compliance has been postponed twice, now to the first business day of November 2027, and in June 2026 the SEC chairman asked staff to review the increments before then, so the change may still be revised.
Why traders care
Wide ticks relative to price, as in low-priced stocks, make spreads expensive in percentage terms. A one-cent spread is 0.04% of a $25 stock but 0.5% of a $2 stock. Futures and options have their own tick schedules set by the exchange; many options trade in $0.05 or $0.01 increments depending on price and program.