 Most dangerous of all to the economy was excessive speculation that had raised stock prices far beyond their value.Some regulators and bankers had warned Coolidge and Hoover that a failure to curb speculation would lead to "one of the greatest financial catastrophes that this country has ever seen," but both presidents were reluctant to become involved with the workings of the Federal Reserve System, which regulated banks.In late October 1929, the Stock Market Crash of 1929 occurred, and the worldwide economy began to spiral downward into the Great Depression.