Excess Returns
Excess returns are the return earned by a stock (or portfolio of stocks) and the risk free rate, which is usually estimated using the most recent short-term government treasury bill.
For example, if a stock earns 15% in a year when the U.S. treasury bill earned 3%, the excess returns on the stock were 15% - 3% = 12%.
Formula
Excess Returns = Return on Asset - Risk Free Rate