# The hidden risk inside your S&P 500 fund

> An index fund of 500 companies sounds spread out, until you see where 38% of your money actually sits.
- Title: The hidden risk inside your S&P 500 fund · Yahoo Finance
- Summary: An index fund of 500 companies sounds spread out, until you see where 38% of your money actually sits. A market cap-weighted S&P 500 fund is far more…
- Keywords: investing, index funds, etfs, diversification, stock market, business, finance, hidden, risk, inside, 500, fund
- Source: Yahoo Finance — https://finance.yahoo.com/markets/stocks/articles/investing-vanguard-p-500-etf-192000849.html
- Published: 2026-09-12T19:20:00+00:00
- Read time: 1 min
- Topics: investing, index funds, etfs, diversification, stock market, business, finance
## You own 500 companies
Buying VOO or SPY makes you a partial owner of 500 of America's biggest businesses. It's the default advice for good reason.
## Buffett said so himself
In his 2016 shareholder letter, Warren Buffett named a low-cost S&P 500 index fund as his standard answer when people ask him where to put their money.

> My regular recommendation has been a low-cost S&P 500 index fund.
## But it's not that spread out
The top 10 holdings are 38% of the fund. The top three alone are 20%. Most of your money sits in a handful of names, not 500.

> The lion's share of your money will be in relatively few of them.
## Nvidia and Apple run the show
Nvidia is 7.55% of the index and Apple 7.04%, with Microsoft at 5.36% and Amazon at 4.13%, per Vanguard data from July 31, 2026.
## The upside of that tilt
Market cap weighting hands the most weight to the biggest winners. Nvidia has averaged 70% annual gains over the past three years.
## The downside in a crash
Corrections come around eventually, and high-tech stocks tend to fall harder than the rest. A long time horizon absorbs that, but it still isn't ideal.
## Small winners barely move it
Costco is 0.57% of the index, Disney 0.26%, FedEx 0.11%, Dollar Tree 0.03%. If one of them triples, your fund hardly notices.
## Equal weight is the fix
A fund like the Invesco S&P 500 Equal Weight ETF (RSP) rebalances quarterly so FedEx and Costco sway the index as much as Nvidia and Apple.
## Key takeaway

A market cap-weighted S&P 500 fund is far more concentrated in a handful of tech giants than the name suggests, and an equal-weight fund fixes that.