A tick is the smallest unit of market activity: a single trade, or a single change in the best bid or ask. Tick data is the complete, time-stamped record of those events. Every chart you see — one-minute candles, daily bars, a price line on a ticker page — is a summary built from ticks.
Trade ticks and quote ticks
Market-data feeds carry two different streams, and tools often blur them together:
- Trade ticks (“time and sales” or “prints”): each executed trade with a time stamp, price, size (number of shares) and the venue where it happened, plus condition codes — for example to flag an odd lot, an extended-hours trade or a late report.
- Quote ticks: each change to the best bid or ask price or size. Quotes change far more often than trades happen, so quote data is many times larger than trade data.
A quote page’s “last price” comes from the trade stream; the bid and ask come from the quote stream. See how to read a stock quote.
Tick size: the minimum price increment
“Tick” also means the smallest price step an instrument can be quoted in:
- US stocks: under SEC Regulation NMS (Rule 612), stocks priced at $1.00 or more are generally quoted in increments of one cent, and stocks under $1.00 in increments of $0.0001. In 2024 the SEC adopted amendments introducing a half-cent increment for certain heavily traded stocks with very tight spreads; check the SEC’s site for the current implementation status.
- Futures: each contract has its own tick size and tick value. The CME E-mini S&P 500 future, for example, moves in 0.25 index-point ticks worth $12.50 per contract.
- Forex: prices are usually quoted to a “pip” (0.0001 for most pairs), with many platforms showing a further fractional digit.
- Other markets set their own tables, often with tick sizes that grow with the share price.
Tick size matters because it sets the minimum possible spread: a stock cannot have a bid–ask spread smaller than one tick.
Upticks, downticks and the NYSE TICK index
A trade at a higher price than the previous trade is an uptick; a lower one is a downtick. Two common uses:
- The TICK index (often shown as
$TICKorTICK) counts how many NYSE-listed stocks last traded on an uptick minus how many last traded on a downtick. It is a short-term gauge of market breadth: strongly positive readings mean broad buying at that moment, strongly negative readings broad selling. - Short-sale rule: the SEC’s Rule 201 (the “alternative uptick rule”) restricts short selling in a stock that has fallen 10% or more from the previous close, generally requiring short sales to be priced above the current best bid for the rest of that day and the next.
Tick charts
Most charts sample by time: one bar per minute, hour or day. A tick chart instead draws a new bar after a fixed number of trades (say every 500 trades). When the market is busy, bars form quickly; when it is quiet, slowly. Some short-term traders like tick charts because each bar represents a similar amount of activity, but they are only meaningful when built from reliable trade data and are rarely available on free widgets.
Why tick data is big — and expensive
- Volume. A liquid stock can produce hundreds of thousands of trades and millions of quote updates in a single day; across a whole market the totals run into billions of messages.
- Precision. Modern feeds time-stamp events to the microsecond or nanosecond, and different venues’ clocks and reporting delays have to be reconciled.
- Licensing. Exchanges charge for real-time and historical data, so full tick histories are usually bought from data vendors rather than downloaded for free.
- Cleaning. Raw ticks include corrections, cancellations, out-of-sequence reports and odd lots that need filtering before analysis.
Tick data vs. the data on this site
The widgets on StockTicker.net show aggregated bars and quotes supplied by TradingView, not raw tick streams. The one-minute candles on the chart are summaries of all the ticks in each minute. For why a price may be delayed or differ from your broker’s, see real-time vs. delayed market data.
Frequently asked questions
What is tick data in the stock market?
Tick data is the complete time-stamped record of individual market events: every trade (price, size, venue) and every change to the best bid or ask. Minute, hourly and daily bars are all built from it.
What is a tick in trading?
A tick is either a single trade or quote update, or the minimum price increment an instrument can move by, for example one cent for most US stocks priced above $1.
What does the TICK index measure?
The NYSE TICK index measures the number of NYSE stocks whose last trade was an uptick minus the number whose last trade was a downtick, giving a moment-by-moment view of market breadth.
This page is general educational content and not investment advice. See the Disclaimer.