This analysis was first published in SvD Näringsliv, in Swedish, on June 6th, 2026. This piece was translated from Swedish by Claude. Some phrasing may differ from a human translation.
The tech boom has changed how you save – even if you haven’t noticed. Now two enormous IPOs could amplify that shift. The best savings advice from years past could suddenly become a major risk.
Warren Buffett wanted to make a bet, but had trouble finding a taker.
The famous billionaire had long argued that ordinary savers were best off putting their money in low-fee index funds. Now he wanted to prove his thesis with a bet that would run for ten years. Could you beat index funds over time?
Buffett found only one person willing to take the other side – hedge fund manager Ted Seides. When the results came in 2017, Buffett had trounced him: 8.5 percent annual returns versus 2.9 percent.
But the safe harbor that index funds once offered is changing significantly. And it’s ordinary savers who are hit hardest.
An index is, roughly speaking, a collection of stocks selected according to specific criteria. You look at things like size, profitability, and the volume of shares available to trade. From that, a selection is made, and some stocks in the index are rotated on a rolling basis.
Each stock’s share of the index normally varies with how its value has developed.
And that’s where something unusual – and risky – has occurred.
Global funds are no longer that global. And broad index funds have become considerably narrower.
Let’s look back ten years, at two different indices: the American S&P 500 (Buffett’s choice in the bet) and the MSCI All Country World Index (ACWI). Both are well-known, large indices that can be traded at low fees.
What has happened is an extreme increase in concentration of American tech companies within these indices. In 2016, the seven largest tech companies represented 12 percent of the S&P 500. Today it’s 37 percent. The equivalent figures in ACWI went from 5.5 percent to 20 percent. An enormous increase.
This also means global funds have become much more American. Swedish funds that track various versions of ACWI – such as SPP Aktiefond Global or AMF Aktiefond Global – have seen the share of American stocks in these funds rise from 52 percent to around 63 percent over ten years.
Given the names of both the indices and the funds, this is probably not entirely obvious to all ordinary savers. The funds aren’t doing anything wrong – they are simply following the indices, which have changed substantially.
When major AI companies like SpaceX and Anthropic are heading toward the stock market, this trend could accelerate. Under normal circumstances, it would take a long time before they could enter any index – not least because they are losing money, which can be a disqualifying criterion.
But now both Nasdaq and FTSE Russell have changed their rules to let SpaceX in faster. That would mean these companies, with their enormous valuations, would quickly find their way into many indices – and through them, many index funds and pension funds. The owners of the S&P 500, however, chose to keep their existing rules, which in practice blocks SpaceX for now.
It’s worth keeping the scale of these IPOs in mind. SpaceX will be the largest IPO in history. When Anthropic and OpenAI reach the stock market, a reasonable assumption is that these three companies alone will have a combined value equal to the entire Stockholm Stock Exchange – three times over. And this for three companies that are currently losing billions of dollars every quarter.
When The Economist looked at the numbers, they concluded that SpaceX, at first, would likely represent only 0.1 percent of the S&P 500. No immediate danger there, regardless of what you think of the valuation. But this is only the beginning of these companies’ journey through the indices. The data from the past ten years speaks clearly.
Has Warren Buffett’s savings advice aged poorly? Are index funds still the best option for ordinary savers?
It is, of course, difficult – and presumptuous – to criticize one of the world’s most successful individual investors. Index funds have delivered, and continue to deliver, good returns. But the reason for that in recent years is primarily that American tech giants have gradually taken an ever-larger share of the funds. Is it reasonable that a global fund consists of 63 percent American stocks? Do all ordinary savers understand that when they buy them?
The coming IPOs of AI companies won’t help either.
Listen to Buffett – but keep in mind that the holdings in index funds look substantially different from what they did when his advice was first given. If this trend continues, the risk is that the funds break down entirely.
The Magnificent 7 is a term for seven of the largest tech companies on the stock market: Alphabet (Google), Amazon, Apple, Meta (Facebook), Microsoft, Nvidia, and Tesla.
