S&P Global

In nineteen fifty seven, a company called Standard & Poor's published a list of five hundred large American companies and decided to track their stock prices together. It was arbitrary at first. But over decades, something incredible happened. That list became the definition of America's largest companies. Trillions in passive index funds now follow it religiously. When you buy an index fund, you are voting with your dollars for everything in that index. S&P decides which companies are in or out. When a company joins the S&P five hundred, its stock usually rises. Trillions flow toward whatever S&P chose to include. The index didn't describe the market.