Why Those Guys Won the Economics Nobels
Harvard Business Review
APRIL 2, 2014
Back in the ‘60s, people developed the capital asset pricing model [CAPM] as a way to do that. Fama said that if you want to say something more about how efficient markets are, how good a job they do of pricing assets, you need some theory of what asset prices should be. And the theory that was available then was CAPM.