what are the common sources of risk 
risk can manifest itself as absolute risk relative risk and or default risk absolute risk as defined by volatility can be easily quantified by common measures like standard deviation relative risk when applied to investments is usually represented by the relation of price fluctuation of an asset to an index or base since the risk free asset used is so short term it is not applicable to either absolute or relative risk default risk which in this case is the risk that the u s government would default on its debt obligations is the risk that applies when using the 3 month t bill as the risk free rate 