S&P 500 · Methodology — How the S&P 500 Is Actually Built
Eligibility thresholds, weighting methodology, and the governance of constituent changes. The rules determine which companies qualify to represent the U.S. large-cap market.
What this page answers
This static page is built to answer searches for S&P 500 · Methodology. It summarizes the live dataset behind the How the S&P 500 Is Actually Built panel and links to the full interactive chart.
Eligibility thresholds, weighting methodology, and the governance of constituent changes. The rules determine which companies qualify to represent the U.S. large-cap market. The data is refreshed by the History of Market pipeline and published as a stable JSON endpoint for research, citation, and AI-agent use.
Latest Snapshot
- Updated
- 2026-02
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Data & Source
GET /api/sp500/rules.json — Canonical dataset endpoint.
Yahoo Finance · Macrotrends · Robert Shiller · FRED · S&P Global · Nasdaq · NBER.
FAQ
Where does this data come from?
History of Market combines public market and macro datasets including Yahoo Finance, Macrotrends, Robert Shiller, FRED, S&P Global, Nasdaq, and NBER. The exact endpoint for this panel is linked below.
How often is it updated?
Daily-tier datasets refresh after the U.S. market close, with a broader weekly refresh on Sunday. The timestamp shown on this page comes from the JSON payload.
Can I use the data?
Yes, for research and education with attribution to History of Market. Upstream data sources retain their own terms.