“Passive funds tend to attract more inflows after the underlying indexes have performed well, so they’re driven by momentum rather than by analysis of company valuations and fundamentals,” according to a recent article in Barron’s.

The article quotes Mike O’Rourke, chief market strategist at Jones Trading, who argues that passive strategies “have a place in the market, but the problem is if they become the market” and when investors believe across-the-board that it’s okay to sacrifice due diligence and “outsource their decision-making process to the Standard & Poor’s index committee.”

Index funds have been a “no-brainer,” the article says, given the gradual rise in the S&P 500 since 2009 (compounded annual return of 15%) and active managers have become “less active over time,” says Martijn Cremers, a professor at the University of Notre Dame. He argues that, in the late 1980s, about half the assets in the active universe were in funds shown to be highly differentiated from indexes. By 2015, however, the level had shrunk to 24%.

This, coupled with the immediate availability of market news, has eaten into the edge once enjoyed by active managers. That said, the article raises the question as to whether the market may be on the cusp of a correction—a time when active managers can shine.

“Markets, like life itself, are a series of ups and downs, and all one can do is maximize the ascent and control the damage on the way down. Autopilot works fine when you’re climbing to cruising altitude, but you might want a skilled pilot when the descent starts.”