M7 · Share of S&P 500 Market Cap — Seven Companies, One Third of the Market: S&P 500 Market Cap Share
Mag 7 share of the S&P 500: 33.5% as of 2026-09-29.
Magnificent 7 Market Cap Share — Combined weight of the Magnificent 7 within the S&P 500, approaching peak concentration levels of the 1970s Nifty Fifty.
The plate
Latest Snapshot
- Observations
- 14
- Sample
- 2018-12-31 – 2026-09-29
The combined share of S&P 500 market capitalization rose from 13% in 2018 to over 33% by year-end 2024, marking the highest concentration in market leaders since the Nifty Fifty era of the early 1970s.
What this page answers
The Magnificent Seven (AAPL, MSFT, NVDA, GOOGL, AMZN, META, TSLA) have expanded from 13.0% of S&P 500 market capitalization in 2018 to 33.5% as of 2026-09-29 (live summation of index weights) — establishing the highest concentration in seven mega-cap leaders since the Nifty Fifty era of the early 1970s.
The combined share of S&P 500 market capitalization rose from 13% in 2018 to over 33% by year-end 2024, marking the highest concentration in market leaders since the Nifty Fifty era of the early 1970s. The data is refreshed by the History of Market pipeline and published as a stable JSON endpoint for research, citation, and AI-agent use.
Magnificent 7 aggregate share of S&P 500 market capitalization (quarterly)
| Date | Weight |
|---|---|
| 2026-09-29 | 33.5% |
| 2026-03-31 | 32.8% |
| 2025-12-31 | 33.5% |
| 2025-06-30 | 32.5% |
| 2024-12-31 | 33.0% |
| 2024-06-30 | 31.0% |
| 2023-12-31 | 28.5% |
| 2023-06-30 | 27.0% |
| 2022-12-31 | 19.5% |
| 2022-09-30 | 18.5% |
| 2021-12-31 | 24.0% |
| 2020-12-31 | 22.5% |
| 2019-12-31 | 16.0% |
| 2018-12-31 | 13.0% |
Complete record (14 rows). Raw dataset: https://historyofmarket.com/api/mag7/concentration.json
Data & Source
GET /api/mag7/concentration.json — Canonical dataset endpoint.
Exchange closing prices · Company filings · Robert Shiller · FRED · NBER.
FAQ
What percentage of the S&P 500 do the Magnificent 7 represent today?
33.5% as of 2026-09-29, up dramatically from 13.0% in 2018.
Where does this data come from?
History of Market combines public market and macro datasets — exchange closing prices, company filings, Robert Shiller, FRED, NBER, and the UBS Global Investment Returns Yearbook (Dimson–Marsh–Staunton). 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.