In practice which market index is most widely used as a proxy for the market portfolio in the CAPM?

Question

Quizplus · Accepted Answer

The S&P 500 is the most widely used market index as a proxy for the market portfolio in the CAPM. It includes 500 large-cap U.S. stocks and is considered a broad representation of the market. The Dow Jones Industrial Average is composed of only 30 large-cap stocks, while the Wilshire 5000 includes all U.S. stocks but is not as commonly used in the CAPM. The Canadian Treasury Bill is not an index of stocks and therefore not relevant in this context.

In Practice Which Market Index Is Most Widely Used as a Proxy