Market performance in the United States is tracked using stock ,
which use formulas to calcuate puce charges.

indexes
quotes
futures
trades

Market performance in the United States is tracked using stock indexes,

which use formulas to calculate price changes.

Explanation:

Stock indices are in itself independent financial or stock markets which also provide a measure of the financial or stock market based on various individual stocks. The USA follows the major stock indices like the Dow Jones Industrial Average (DJIA), S&P 500, and Nasdaq Composite.

All these are either market (S&P 500) or price-weighted (DJIA). Stock indices are calculated based on the per-share price of the stocks of a company.

Any changes in the price(change from previous closing price value of the share) of a company’s share is watched closely by the investors and compared with the current price.