Almost a century ago, the stock market crash of 1929 and the resulting crisis of investor confidence spawned today's securities laws—specifically, the Securities Act of 1933 and the Securities Exchange Act of 1934.

In the lead-up to the stock market crash of 1929, some $50 billion of new securities were floated in the United States. Half—or $25 billion worth of the securities floated during that period—proved to be worthless. In today's terms, adjusted for inflation, investor losses exceeded half a trillion dollars. Investor confidence, and confidence in U.S. markets specifically, was at its nadir.

Today, U.S. capital markets are the largest and most liquid in the world. As of 2023, U.S. equity markets totaled more than $46.2 trillion in market capitalization. U.S. markets account for approximately 41 percent of global equity and 40 percent of global fixed income. The European Union (EU) ranks a distant second at 11.1 percent of global equity capitalization, followed by China (10.6%), Japan (5.4%), and Hong Kong (4%). The "Magnificent Seven"—Apple, Microsoft, Google, Amazon, Nvidia, Meta, and Tesla—have combined market capital larger than any foreign stock market.