Tick

Tick is a measure of minimum upward or downward movement in the price of a security. A tick can also refer to the change in the price of security from trade to trade.

If a trade is at higher price than its last traded price by it’s tick size or more, then it is called uptick.

Similarly, if a trade is at a lower price than its last traded price by it’s tick size or more, then it is called downtick.

 

For example; If the tick size is $0.01 and the stock goes from $10 to $10.01 then it would be considered as an uptick. Conversely, if it goes from $10 to $9.99, it would be a downtick.

Also, if a stock had a tick size of $0.1 and a current price of $10, the associated price can move to $10.1, $10.2 or $9.9, $9.8 but cannot move to $10.05 or $9.95 as it does not meet the tick size of $0.1.