I'm teaching Corporate Finance again this semester. In the class, we spend a fair bit of time on the CAPM (yes, I know - it's not perfect. But it is a still pretty good). One of the big issues is what to use as the Market Risk Premium (or, as it's sometimes called, the "Equity Risk Premium). Looks like I'll be using this piece as background: The Equity Risk Premium in 100 Textbooks by Pablo Fernandez of the University of Navarra. Here's the abstract:
I review 100 finance and valuation textbooks published between 1979 and 2008 (Brealey, Myers, Copeland, Damodaran, Merton, Ross, Bruner, Bodie, Penman, Weston, Arzac...) and find that their recommendations regarding the equity premium range from 3% to 10%, and that several books use different equity premia in different pages.
Some confusion arises from not distinguishing among the four concepts that the word equity premium designates: Historical equity premium, Expected equity premium, Required equity premium and Implied equity premium.
Finance professors should clarify the different concepts of equity premium and convey a clearer message about their sensible magnitudes.