Importantly, this result will be independent of the investor's level of risk aversion, and / or assumed utility function, thus providing a readily determined discount rate for corporate finance decision makers as above,[19] and for other investors. The argument proceeds as follows: If one can construct an efficient frontier—i.e. each combination of assets offering the best possible expected level of return for its level of risk, see diagram—then mean-variance efficient portfolios can be formed simply as a combination of holdings of the risk-free asset and the "market portfolio" (the Mutual fund separation theorem), with the combinations here plotting as the capital market line, or CML. Then, given this CML, the required return on risky securities will be independent of the investor's utility function, and solely determined by their covariance ("beta") with aggregate, i.e. market, risk.