At first, it appears that we are not given the information needed to calculate the holding period, or expected return (beginning price, ending price, or annual dividend). However, we are given the information required to calculate the required return (CAPM) and since Portfolio Z is on the SML, we know that the required return (RR) equals the expected return (ER). So, ER = RR = R_f + (ER_M – R_f) × Beta = 7.0% + (13.0% − 7.0%) × 1.3 = 14.8%.

The SML plots beta (or systematic risk) versus expected return, the CML plots total risk (systematic plus unsystematic risk) versus expected return. Portfolio Y is overvalued – any portfolio located below the SML has an RR > ER and is thus overpriced. Since Portfolio X plots above the SML, it is undervalued and the statement should read, “Portfolio X’s required return is less than the market expected return.”