Final answer:
To ensure the portfolio is as risky as the market, the beta of the other stock in the portfolio must be 0.66 if the portfolio includes a risk-free asset and another stock with a beta of 1.34.
Step-by-step explanation:
The question asks for the beta of the other stock in a portfolio that includes a risk-free asset and two stocks, one with a known beta of 1.34. To determine the beta of the other stock, we need to understand that the beta of the entire portfolio should be equal to the market's beta, which is 1 since the portfolio is equally as risky as the market.
The formula for the beta of a portfolio (βportfolio) is the weighted average of the betas of the individual assets, where weights are the proportions of the investment in each asset. For a two-asset portfolio with a risk-free asset (which has a beta of 0), the calculation would be:
βportfolio = (0.5 * βstock1) + (0.5 * βstock2)
Given the portfolio's beta is 1 (equal to the market) and one of the stocks has a beta of 1.34, we can set up the equation:
1 = (0.5 * 1.34) + (0.5 * βstock2)
By solving for βstock2, we find the beta for the other stock.
1 = 0.67 + (0.5 * βstock2)
βstock2 = (1 - 0.67) / 0.5
βstock2 = 0.66
Therefore, the beta for the other stock must be 0.66 to ensure the portfolio has the same risk level as the market.