Have S&P 500 Index Funds, Often Touted as the Best Stock Investments, Become Dangerous? There’s a Worrisome Development — and a Possibly Better Alternative.

What’s the investment I’ve recommended most often for most people? A low-fee exchange-traded fund (ETF) that tracks the S&P 500 index, such as the Vanguard S&P 500 ETF (NYSEMKT: VOO) or the SPDR S&P 500 ETF (NYSEMKT: SPY). I suspect many of my colleagues would say the same. Even Warren Buffett has recommended it. In his 2016 letter to shareholders, he noted, “Over the years, I’ve often been asked for investment advice… My regular recommendation has been a low-cost S&P 500 index fund.”

So I’m sorry to point out that it’s not a perfect kind of investment. It has some issues.

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What’s wrong with the S&P 500?

Here’s a big one: It’s way more concentrated than most people realize. For example, check out its recent top 10 components:

Data: Slickcharts.com, on June 12, 2026.

Those weightings may not seem huge until you remember that there are about 490 other companies. These 10 above represent about 2% of the index’s holdings but 39% of its total value. So if you invest in the S&P 500 because it’s a great way to be quickly and easily invested in 500 of America’s biggest companies, you are invested in those companies, but more than a third of your investment is in these 10 companies alone.

Here are the weightings of some other companies:

Data: Slickcharts.com, on June 12, 2026.

As you can see, you won’t have much invested in the vast majority of the companies.

That can be OK, though. Maybe you like those tech heavyweights in the top 10 — which include all of the “Magnificent Seven” stocks (Apple, Amazon, Alphabet, Meta Platforms, Microsoft, Nvidia, and Tesla). Maybe you want to invest in the 500 companies, with most of your money going to the biggest. After all, most of them have grown very rapidly over the past few years.

Keep in mind, though, that when there’s a stock market crash or correction, as there invariably is now and then, those high-flying growth stocks are often the ones that fall harder. That, too, can be OK as long as you have a very long-term investing period. But it’s not ideal.

Is there a better alternative to the S&P 500?

There is an alternative to standard S&P 500 index funds that’s worth considering: An equal-weighted one. Standard ones are weighted by market cap, meaning the larger a company’s market cap, the greater its weighting. The Invesco S&P 500 Equal Weight ETF (NYSEMKT: RSP), in contrast, is equal-weighted. The 500 components are rebalanced quarterly, so between rebalancings you’ll see fluctuations in the weightings as various stocks gain or lose value from day to day and year to year. Check out its recent top 10 holdings:

Data: Morningstar.com, June 10, 2026.

Note that Micron Technology appears in both top 10 lists, but in the earlier one, it has a 1.67% weighting, while in the fund above, it has a much lower weighting of 0.35%. This kind of index fund has you much more invested in the other 490 stocks beyond the top 10 — though, of course, each stock has a relatively minor weighting. But every promising stock will have an equal chance of outperforming for you.

An equal-weighted S&P 500 ETF may not grow as fast as a market-cap-weighted one, but during a market downturn, it may hold its value a bit more. Over the past 15 years, this ETF has averaged annual gains of about 12%, while the Vanguard S&P 500 ETF has averaged 14.4%. There’s a trade-off, but it’s not enormous. Give equal-weighted S&P 500 index funds some consideration.

Should you buy stock in Vanguard S&P 500 ETF right now?

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Selena Maranjian has positions in Advanced Micro Devices, Alphabet, Amazon, Apple, Berkshire Hathaway, Broadcom, Meta Platforms, Micron Technology, Microsoft, Nvidia, and Pfizer. The Motley Fool has positions in and recommends Advanced Micro Devices, Alphabet, Amazon, Apple, Berkshire Hathaway, Broadcom, Hewlett Packard Enterprise, Intel, Meta Platforms, Micron Technology, Microsoft, Nvidia, Pfizer, Tesla, Vanguard S&P 500 ETF, and Western Digital. The Motley Fool recommends Kroger and ON Semiconductor and recommends the following options: long January 2028 $320 calls on McDonald’s and short January 2028 $340 calls on McDonald’s. The Motley Fool has a disclosure policy.

Have S&P 500 Index Funds, Often Touted as the Best Stock Investments, Become Dangerous? There’s a Worrisome Development — and a Possibly Better Alternative. was originally published by The Motley Fool