I just came across this financial blog called Finance Profession.com. It is by a finance professor at St. Bonaventure University. Right on the front page there is a great article debating the validity of CAPM with a link to Empirical Finance LLC.
If you are interested in a Master in Finance (you should be if you are looking at my site ha!) this site is a really good info source for classwork and outside of class. It includes write ups from recent research, news, capital markets information, etc. A great site to get you up to speed on the underlying theory of finance.
