Open, High, Low, Close — the four prices that summarize a security's trading activity within a single period, forming the basis of bar and candlestick charts.
OHLC stands for the four data points captured for each time period on a price chart: the Open (the first traded price of the period), the High (the highest price reached), the Low (the lowest price reached), and the Close (the final traded price). Together these four values compress all of a period's trading into a single, information-dense unit. A period can be any interval — one minute, one hour, one day, one week — and each produces its own OHLC tuple.
OHLC data is the raw material for the two most common chart types in technical analysis. An OHLC bar draws a vertical line from the low to the high, with a small left tick marking the open and a right tick marking the close. A candlestick uses the same four values but renders the open-to-close range as a colored "body" (green or white when the close is above the open, red or black when below) with thin "wicks" extending to the high and low. Both encode identical information; candlesticks simply make the open-close relationship more visually immediate.
The relationship between the four values within a single bar carries meaning. A close near the high after opening near the low signals strong buying pressure through the period; the reverse signals selling pressure. Long wicks reveal rejected price extremes — a long upper wick shows buyers pushed price up but sellers drove it back down. Nearly all technical indicators are derived from OHLC inputs: moving averages typically use the close, the Average True Range uses high-low ranges and gaps, and candlestick patterns like dojis and engulfing bars are defined entirely by OHLC geometry.
This definition is for informational and educational purposes only. Nothing on Finance Compass constitutes financial, investment, or trading advice. Always conduct your own research and consult a qualified professional before making financial decisions.