sp500-data

Daily-updated US stock ticker CSVs from Nasdaq, including S&P 500 constituents and industry-grouped lists, plus a free public HTTPS API.

Approximate bottom-up S&P 500 return replication from historical constituents, estimated weights, constituent returns, and daily contribution attribution. Independent project; not affiliated with or endorsed by S&P Dow Jones Indices. Inferred weights are not official index data.

Free market data samples and reproducible Python examples for backtesting and quantitative research.