S&P 500 (SP500) perpetual market

The S&P 500 is the most widely followed stock market index in the world, tracking the performance of about 500 of the largest publicly traded companies in the United States. Maintained by S&P Dow Jones Indices, it is weighted by market capitalization, so bigger companies have more influence, and it spans every major sector, which makes it the standard benchmark for the overall US stock market and a proxy for the American economy. Trillions of dollars are managed against it through index and exchange-traded funds, and it underlies a vast market in futures and options. Its long-run upward trajectory, punctuated by crashes and recoveries, is often used to illustrate equity returns over time. In recent years the index has become increasingly concentrated in a handful of very large technology companies, so its direction is heavily influenced by the fortunes of the biggest names in artificial intelligence and computing.