Final answer:
VTSAX tracks the CRSP US Total Market Index, offering broad exposure to about 7,000 U.S. companies across all sectors and sizes, as opposed to narrower indices like the S&P 500 or the Dow Jones Industrial Average.
Step-by-step explanation:
The Vanguard Total Stock Market Index Fund (VTSAX) aims to give investors exposure to the entire U.S. equity market, including small-, mid-, and large-cap growth and value stocks. The stock index that VTSAX tracks is the CRSP US Total Market Index, which includes essentially all U.S. companies with stock ownership.
Unlike the Standard & Poor's 500 index or the Dow Jones Industrial Average, which are more narrow indices representing either the 500 largest U.S. companies by market capitalization or 30 large industrial stocks, respectively, the CRSP US Total Market Index captures about 7,000 firms and is designed to represent the broad investment results of the overall market.