RISKLESS RATES AND RISK PREMIUMS All models of risk and return in finance are built around a rate that investors can make on riskless investments and the risk premium or premiums that investors should charge for investing in the average risk investment. In the capital asset pricing model, where there is only one source of market risk captured in the market portfolio, this risk premium becomes the premium that investors would demand when investing in that portfolio. In multi-factor models, there are multiple risk premiums, each one measuring the premium demanded by investors for exposure to a specific risk factor. In this chapter, we examine how best to measure a riskless rate and to estimate a risk premium or premiums for use in these models. As noted in chapter 4, risk is measured in terms of default risk for bonds and this default risk is captured in a default spread that firms have to pay over and above the riskless rate. We close this chapter by considering how best to estimate these default spreads and factors that may cause these spreads to change over time. The Risk Free Rate Most risk and return models in finance start off with an asset that is defined as risk free and use the expected return on that asset as the risk free rate. The expected returns on risky investments are then measured relative to the risk free rate, with the risk creating an expected risk premium that is added on to the risk free rate. But what makes an asset risk free? And what do we do when we cannot find such an asset? These are the questions that we will deal with in this section. Requirements for an Asset to be Riskfree In chapter 4, we considered some of the requirements for an asset to be riskfree. In particular, we argued that an asset is riskfree if we know the expected returns on it with certainty – i.e. the actual return is always equal to the expected return. Under what conditions will the actual returns on an investment be equal to the expected returns? In our view, there are two basic conditions that have to be met. The first is that there can be no default risk. Essentially, this rules out any security issued by a private firm, since even