Cliff Asness Is ‘Old Man Whinging’ as Markets Get Less Efficient

Cliff Asness says he sounds like an “old man whinging,” but that’s not stopping him from writing 23 pages on his latest thesis: Financial markets these days aren’t what they were.

The often-cantankerous co-founder of AQR Capital Management just published new research that amounts to a detailed exposition of an argument he has repeatedly raised of late, namely that the market has become less efficient over the course of his more than three-decade career.

The paper — prepared for the 50th anniversary issue of The Journal of Portfolio Management — is “as much an op-ed as it is quantitative research,” the billionaire admits. But he says the conclusions have important implications for any investor seeking to win on Wall Street.

“I believe markets have gotten less efficient over the 34 years since the data in my dissertation ended,” writes Asness, 57. “I think the ups and downs will be bigger and last longer, making more money for those who can stick with it long term, but making it harder to do so.”

In one sense, it’s a big call coming from the hedge-fund executive. His PhD adviser at the University of Chicago was Eugene Fama, the godfather of what’s known as the efficient markets hypothesis.

In that world view, trying to outguess markets is a fool’s errand, but it’s possible to eke out extra returns by picking stocks based on so-called factors, or characteristics that compensate their holders for bearing particular risks. It’s the philosophy at the heart of firms like AQR and Dimensional Fund Advisors, another business founded by Fama’s proteges.

If Asness is correct that markets are getting less efficient, it essentially means that factor-investing approach is getting harder. It may take much longer for the type of strategy beloved by AQR to come good.

In terms of what has caused the change, Asness says that index investing, ultra-low interest rates and social media are all potential suspects. He ultimately lands on the latter and a subsequent “gamification” of trading as likely having the biggest effect, as it has ushered many irrational actors into the investment world.

“Whether this lasts forever I can’t say,” Asness writes in the paper, titled The Less-Efficient Market Hypothesis. “It seems that over history new technologies are eventually adapted to, and one day maybe that adaptation renders this piece obsolete. But for now, I think it has raised the stakes of rational active investing.”