Market performance in the United States is tracked using stock indexes which use formulas to calculate price changes.
Step-by-step explanation:
A stock index or stock market index is a measure of a segment of the stock market.Market exhibition relates to the execution of effects of these policies—the connection of selling price to costs, the size of output, the facility of production, progressiveness in procedures and products, and so forth. The New York Stock Exchange (abbreviated as NYSE, and nicknamed "The Big Board"), is an American stock market located at 11 Wall Street, Lower Manhattan, New York City, New York.