A measure of the total market value of an equity market. The measure is calculated by taking the market capitalization of all companies in the equity market and adding them together to arrive at the capitalization for the market as a whole. Taobiz explains Equity Market Capitalization The measure is used to compare the increase or decrease in the size of the market as a whole. The measure is also used to compare the value of the equity market to other segments of the economy, such as the value of the real estate market.