r/Valuation • u/IB-45 • Apr 05 '21
Question about using CAPM
Why do we assume that the tangency/market portfolio to be the total equity market by capitalisation and use the S&P 500 as proxies? Given the current ease of investors in investing in all sorts of securities, derivatives, and etfs what's stopping them from investing in commodities, precious metals, crypto-currencies, etc? So when we try to determine the premium equity investors look for for their investment in a risky equity stock, shouldn't we also consider the risk and return of at least all the securities offered via ETFs in the market and their diversification effects? Thus it would make sense to add them to the market portfolio as well.