EFF: The premise of the Fox book is that our current economic problems are largely due to blind acceptance of the efficient markets hypothesis (EMH), which posits that market prices reflect all available information. The claim is that the world's investors and their advisors in the financial industry bought into this model. Because they ceased to investigate the true value of assets, we have been hit with "bubbles" in asset prices. The most recent is the rise and sharp decline in real estate prices which froze financial markets and led to the worst recession since the Great Depression of the 1930s.
The book is fun reading, but its main premise is fantasy. Most investing is done by active managers who don't believe markets are efficient. For example, despite my taunts of the last 45 years about the poor performance of active managers, about 80% of mutual fund wealth is actively managed. Hedge funds, private equity, and other alternative asset classes, which have attracted big fund inflows in recent years, are built on the proposition that markets are inefficient. The recent problems of commercial and investment banks trace mostly to their trading desks and their proprietary portfolios, and these are always built on the assumption that markets are inefficient. Indeed, if banks and investment banks took market efficiency more seriously, they might have avoided lots of their recent problems. Finally, MBA students who aspire to high paying positions in the financial industry have a tough time finding a job if they accept the EMH.
I continue to believe the EMH is a solid view of the world for almost all practical purposes. But it's pretty clear I'm in the minority. If the EMH took over the investment world, I missed it.
The Fox book is an example of a general phenomenon. Finance, financial markets, and financial institutions are in disrepute. The popular story is that together, they caused the current recession. I think one can take an entirely different position: financial markets and financial institutions were casualties rather than the cause of the recession.
But suppose we buy into the more common negative current view of finance. There is still a big open question. Beginning in the early 1980s, the developed world and some big players in the developing world experienced a period of extraordinary growth. It's reasonable to argue that in facilitating the flow of world savings to productive uses around the world, financial markets and financial institutions played a big role in this growth. Despite any role of finance in the current recession, are the market naysayers really ready to argue that worldwide wealth would be higher today if financial markets and financial institutions didn't develop as they did?
Toward the end of the book, Fox concludes that passive investing is the right choice for almost all investors. My academic friends in behavioral finance (for example, Richard Thaler) almost always end up with a similar conclusion. In my view, this is an admission that the EMH provides a good view of the world for almost all practical purposes. At which point, I say I won.
Eugene Fama and Ken French are members of the Board of Directors of the general partner of, and provide consulting services to Dimensional Fund Advisors LP.