Stock market data

Stock market data is the record of what traded, at what price and when. Quant funds use it for backtesting and execution research, asset managers for performance and risk, fintech apps for charts and portfolios, and academics for event studies.

Typical fields:

• Ticker, exchange and a stable identifier (ISIN, FIGI or CUSIP where licensed)
• Open, high, low, close and volume per bar, or individual trades and quotes for tick data
• Corporate actions: splits, dividends, spin-offs, symbol changes and delistings
• Adjustment factors and trading calendars

Sources and collection

Data originates from exchange feeds and consolidated tapes. Vendors capture it in real time or license it from exchanges, then normalize symbols, apply corporate actions and fill gaps. Quality depends on how carefully they handle symbol changes, halts, odd lots and late corrections.

Delivery and pricing

Daily and minute bars usually arrive as files (CSV or Parquet) or through a REST API; tick data is delivered as bulk history plus a streaming feed. Pricing scales with granularity, number of exchanges, history depth and usage, and tick data costs far more than daily bars. Displaying real-time or delayed prices to end users typically requires exchange agreements and fees on top of the vendor licence.

Before you buy

• Check that delisted and bankrupt companies are included, otherwise backtests carry survivorship bias.
• Confirm whether prices are raw, split-adjusted or fully adjusted, and that adjustment factors are supplied.
• Compare a sample of bars against a second source for a volatile day.
• Ask whether timestamps are exchange time or receipt time, and in which time zone.
• Read the display and redistribution terms before building a customer-facing product.