The 1929 stock market crash—famously known as Black Tuesday—was caused by a combination of rampant speculative stock buying fueled by excessive margin debt, overproduction in agriculture and manufacturing, stagnant wages, and underlying weaknesses in the banking sector. During the 1920s, stock prices detached drastically from real corporate earnings as everyday citizens and institutional investors borrowed heavily to buy equities. When speculative confidence finally shattered in late October 1929, an unprecedented wave of panic selling erupted, wiping out billions of dollars in wealth, triggering massive bank runs, and helping to catalyze the Great Depression.