Seven companies account for roughly a third of S&P 500 value, Insight Guru says
SPY•Seven companies accounted for roughly one-third of the S&P 500’s value at Tuesday’s close, with a combined value of about $23 trillion. The index’s 10 largest companies represented almost 40% of its value in mid-2025, compared with under 20% in 2015.
1. Index concentration rises
Seven companies accounted for roughly one-third of the S&P 500 at Tuesday’s close, with a combined value of about $23 trillion. The 10 largest companies reached almost 40% of the index’s value in mid-2025, compared with under 20% in 2015 and more than 25% at the dot-com peak in 2000.
2. Overlapping holdings
Apple, Nvidia and Microsoft alone were valued at $13.1 trillion. Holdings across index funds, technology funds and 401(k) accounts can overlap, increasing investors’ exposure to the same seven companies.
