Legal Definitions - market portfolio

A market portfolio is a collection of all the assets in a particular market. It is a value-weighted portfolio that includes every asset in the market.

Investors hold various securities or other investments in a portfolio to diversify risk. For example, an investor may hold stocks, bonds, and real estate in their portfolio. By diversifying their investments, they can reduce the risk of losing money if one investment performs poorly.

For instance, suppose an investor holds a market portfolio that includes stocks from every industry in the stock market. If one industry performs poorly, the investor's overall portfolio may not be affected significantly because they have investments in other industries that may perform well.