Apple’s weighting in a number of benchmarks has been low for years because Buffett’s Berkshire Hathaway Inc. holds its investments for the long term, making them non-tradable. Therefore, index providers calculated the technology company’s weighting based on a method known as float-adjusted market capitalization.

Simply put, Apple’s true value is not reflected in many indices.

In percentage terms, the numbers don’t seem huge – the S&P 500, for example, currently accounts for 94 percent of Apple’s value. According to Piper Sandler & Co., this value is now likely to rise to 100 percent. But for a $3 trillion company, it adds up.

After Berkshire’s sale, passive funds tracking those indexes may need to buy as much as $40 billion worth of Apple stock in their next reallocation, Piper Sandler estimates. That’s three times the average daily trading volume of the company’s shares over the past month.

Index funds robotically replacing another investor in one of the megacaps will give ammunition to critics like David Einhorn, who argue that passive investing has “fundamentally destroyed” the markets because so much money has become insensitive to value. More immediately, this is bad news for some other companies in the benchmarks, whose weightings will be reduced to reflect the change and whose shares will be sold by the funds accordingly.

The first changes will not be made until next month’s quarterly index adjustment, and for now at least, any changes seem secondary to a market fixated on economic growth and central bank policy. But there is a group of traders who are taking positions in anticipation of such events.

“We frequently see activity on our desk due to reshuffles,” said Michael Kantrowitz, chief investment strategist at Piper Sandler. “People want to be informed.”

A spokesman for S&P Dow Jones Indices referred Bloomberg News to the index methodology and declined further comment.