"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."
"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."