By TheStreet Staff What Is the Wilshire 5,000 Stock Market Index?The Wilshire 5,000 Total Market Index is a stock market index that tracks the performance of (nearly) the entirety of the publicly traded U.S. equity market. Like other stock indexes, it is a collection of stocks whose aggregate performance can be used as a sort of barometer for the market. It comprises thousands of American stocks and is considered by many investors and analysts to be the most accurate gauge of the U.S. stock market at large. The Wilshire 5,000 is so named because, at its inception in 1974, it included around 5,…