OHLCV

OHLCV contains five data points for every time period (bar) in a price chart. The Open is the price of the first trade that occurred during the bar's time window — for a daily bar, it is the first trade of the regular session (9:30 AM ET for US equities). The High is the highest price reached by any trade during the period. The Low is the lowest price. The Close is the price of the last trade before the period ends — for daily bars, this is the 4:00 PM ET closing price. Volume is the total number of shares (equities), contracts (futures), or units (crypto) traded during the period.

These five values capture the full story of price action within any time period: where price started, the extremes reached in both directions, where price settled, and how much activity accompanied the movement. Volume is particularly important — high-volume moves are considered more significant and reliable than low-volume moves, which may be easily reversed.

Candlestick charts are the most common way to display OHLCV data. Each candle represents one time period and encodes all five values visually. The candle body spans from the open to the close. A green (bullish) candle has a close above the open; a red (bearish) candle has a close below the open. The upper wick (shadow) extends from the top of the body to the High. The lower wick extends from the bottom of the body to the Low. Volume is displayed as a bar below the price chart, typically colored to match the candle.

This visual encoding makes patterns immediately recognizable: a long upper wick with a small body signals rejection at higher prices (sellers overpowered buyers). A long lower wick signals rejection at lower prices (buyers stepped in aggressively). A large bullish body spanning most of the bar's range with above-average volume is a strong buying candle. Entire candlestick pattern libraries (doji, engulfing, hammer, shooting star) are built on reading the relationship between these OHLCV components within a single bar or across consecutive bars.

OHLCV data is available at any time resolution, and bar selection significantly affects which patterns and indicators are meaningful. One-minute bars capture intraday micro-fluctuations, useful for scalping but noisy for swing trading. Five-minute and fifteen-minute bars are the most commonly used timeframes for intraday day trading strategies — they balance granularity with noise reduction. Hourly bars reveal intraday trends useful for options traders and swing traders targeting multi-day moves. Daily bars are the standard for position traders, fundamental traders, and most technical pattern analysis (head and shoulders, cup and handle, etc.). Weekly bars smooth out noise further for longer-horizon investors and work well for identifying major support and resistance zones.

Most technical indicators are calibrated for specific timeframes. A 14-period RSI on 1-minute bars measures momentum over 14 minutes; on daily bars, it covers nearly three weeks. Using the same indicator settings across wildly different timeframes without adjustment produces misleading signals. Tradewink computes indicators across multiple timeframes — 5-minute, 15-minute, and daily — and synthesizes them for a multi-timeframe view of market conditions.

Every standard technical indicator is derived from some combination of OHLCV components. Moving averages (SMA, EMA) use only the close prices to smooth price action over time. The Relative Strength Index (RSI) uses close-to-close changes to measure momentum. Bollinger Bands use the close to compute a moving average and standard deviation bands. The Average True Range (ATR), a key measure of volatility, uses the high, low, and previous close to capture the true range of each bar. VWAP (Volume-Weighted Average Price) uses close and volume together to compute the average price weighted by trading activity. The MACD uses two exponential moving averages of the close. Stochastic oscillators use the high and low alongside the close to measure where the current price sits within its recent range.

Virtually every price-based technical indicator traces back to OHLCV inputs. The richness of OHLCV — capturing both price range and participation — explains why it has remained the standard data format across all asset classes and time periods since candlestick charting originated in 18th-century Japan.

OHLCV data quality varies significantly across providers, which directly affects the reliability of technical analysis and backtesting. Common data quality issues include: adjusted vs. unadjusted prices (historical data must be adjusted for splits and dividends to produce accurate percentage returns), survivorship bias (databases that only include currently-listed stocks overstate historical returns), and timestamp alignment (bars from different providers may use different time boundaries for the same nominal period).

For US equities, Polygon.io and Alpaca provide high-quality intraday OHLCV data with sub-second timestamp precision. Yahoo Finance (yfinance) provides free daily-bar data adequate for casual backtesting but with known quality issues for certain periods and tickers. For crypto, exchange APIs (Binance, Coinbase) provide OHLCV directly. For futures, data vendors like Norgate Data and CSI Data specialize in continuous-contract adjusted series that handle rollover correctly. Tradewink uses Polygon.io as its primary market data source with yfinance as a fallback, ensuring high-quality OHLCV inputs for all signal generation and strategy evaluation.