The U.S. stock market is becoming increasingly dependent on three mega-cap technology companies — Nvidia Corp. (NASDAQ:NVDA), Apple Inc. (NASDAQ:AAPL) and Microsoft Corp. (NASDAQ:MSFT).
The trio now accounts for more than 21% of the S&P 500, according to Creative Planning data cited by Yahoo Finance, marking the highest concentration in just three stocks in the benchmark’s history. By comparison, IBM (NYSE:IBM), AT&T Inc (NYSE:T) and ExxonMobil Holdings Corp (NYSE:XOM) together represented 13.4% of the S&P 500 at their peak in the mid-1980s.
That concentration matters for ETF investors because the largest S&P 500 funds are market-cap weighted, meaning the biggest companies receive the largest allocations.
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The SPDR S&P 500 ETF Trust (NYSE:SPY) has Nvidia at 8.63%, Apple at 7.25% and Microsoft at 5.82%. Together, the three accounted for roughly 21.7% of SPY.
The Vanguard S&P 500 ETF (NYSE:VOO) showed a similar concentration, with Nvidia at 8.08%, Apple at 7.03% and Microsoft at 5.69%. That puts the combined exposure at about 20.8%.
This means investors buying broad-market ETFs are getting substantial exposure to the performance of just three companies, even though the funds hold hundreds of stocks.
The concentration is even more pronounced in the Invesco QQQ Trust (NASDAQ:QQQ), which tracks the Nasdaq-100.
Nvidia represents 8.53% of QQQ, Apple 7.2% and Microsoft 5.78%. Combined, the three accounted for roughly 21.5% of the ETF.
The distinction is important: while QQQ offers exposure to 100 companies, its portfolio remains heavily tilted toward the largest technology and growth names.
For investors looking to reduce this mega-cap concentration, the Invesco S&P 500 Equal Weight ETF (NYSE:RSP) takes a different approach, assigning roughly equal weights across S&P 500 constituents rather than allowing the largest companies to dominate the portfolio. RSP had 508 holdings.
With Nvidia, Apple and Microsoft driving a record share of the S&P 500, the growing question for ETF investors is no longer simply whether they own the broader market — but how much of that market is effectively riding on three stocks.
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