OHLC

OHLC stands for Open, High, Low, Close — the four essential data points that describe a security's price action during any time period (a minute, hour, day, week, or month). Together, these four values form the foundation of nearly all technical analysis.

The Open is the first traded price when the period begins. On the NSE, the daily opening price for a stock is determined during the pre-open session (9:00–9:08 AM) through a call auction mechanism, where buy and sell orders accumulate and the exchange calculates the equilibrium price. The High and Low are the maximum and minimum prices reached during the period. The Close is the last traded price — for Indian equities, the official closing price is calculated as the weighted average of the last 30 minutes of trading (2:30–3:30 PM) to prevent manipulation.

OHLC data is visually represented through two main chart types: bar charts and candlestick charts. Candlestick charts (originating from 18th-century Japanese rice traders) are dominant on Indian trading platforms. A green/white candle means the close was above the open (bullish period), while a red/black candle means the close was below the open (bearish period). The body shows the open-close range; the wicks/shadows show the high-low range.

Specific OHLC patterns carry predictive significance. A "doji" candle (open ≈ close, forming a cross shape) signals indecision. A "hammer" (small body at the top, long lower shadow) after a downtrend signals potential reversal. A "marubozu" (no shadows, open = low and close = high for bullish, or vice versa) signals strong directional conviction.

All technical indicators — Moving Averages, MACD, RSI, Bollinger Bands — are ultimately derived from OHLC data. Understanding OHLC is therefore not just about reading a chart; it is understanding the raw material from which all technical analysis is built.