---
type: "Topics"
locale: "en"
url: "https://longbridge.com/en/topics/100000000948791.md"
description: "Nearly half of the entire S&P 500 now sits in just 15 companiesThe 15 largest companies make up about 46% of the index by weight, per Slickcharts data this morning. The other 485 share the remaining 54%$NVIDIA(NVDA.US) alone is about 7.4% of the index. That's as much as the 237 smallest S&P 500 stocks combined$NVIDIA(NVDA.US), $Apple(AAPL.US), $Alphabet(GOOGL.US) and $Microsoft(MSFT.US) together are more than a quarter of the index at roughly 26%Two of those 15 report after the bell tonight, $Meta Platforms(META.US) and $Tesla(TSLA.US), worth about 4.6% of the index between themThis is why owning "the whole market" isn't the diversification it sounds like. Most index fund money is now riding on a handful of AI-linked giants, so a single earnings night like tonight can move the S&P more than hundreds of smaller companies ever couldSource: StockMarket.News"
datetime: "2026-10-21T15:06:49.000Z"
locales:
  - [en](https://longbridge.com/en/topics/100000000948791.md)
  - [zh-CN](https://longbridge.com/zh-CN/topics/100000000948791.md)
  - [zh-HK](https://longbridge.com/zh-HK/topics/100000000948791.md)
author: "[StockMarket.News](https://longbridge.com/en/profiles/21806507.md)"
generator: "portal-rs"
---

# Nearly half of the entire S&P 500 now sits in …


### Related Stocks

- [META.US](https://longbridge.com/en/quote/META.US.md)
- [TSLA.US](https://longbridge.com/en/quote/TSLA.US.md)
- [.SPX.US](https://longbridge.com/en/quote/.SPX.US.md)
- [NVDA.US](https://longbridge.com/en/quote/NVDA.US.md)
- [MSFT.US](https://longbridge.com/en/quote/MSFT.US.md)
- [MSFD.US](https://longbridge.com/en/quote/MSFD.US.md)
- [MSFU.US](https://longbridge.com/en/quote/MSFU.US.md)
- [MSFY.US](https://longbridge.com/en/quote/MSFY.US.md)
- [MSFX.US](https://longbridge.com/en/quote/MSFX.US.md)
- [MSFO.US](https://longbridge.com/en/quote/MSFO.US.md)

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> **Disclaimer: This article is for reference only and does not constitute any investment advice.**