Name the U.S. President whose encouragement of business speculation lead the stock market from boom to bust in 1929?

The 30th U.S. President, often known as "Silent Cal," presided over most of the "Roaring Twenties," an era of dramatic economic growth and cultural change. A firm believer in laissez-faire economics, he famously declared that "the chief business of the American people is business." His administration championed policies that reflected this belief, including significant tax cuts for corporations and the wealthy and a marked reduction in government regulation and oversight of the financial industry.

This hands-off approach created an environment ripe for unchecked speculation. With easy credit and a popular belief in endless prosperity, millions of Americans poured money into the stock market, often buying stocks "on margin" with borrowed funds. This speculative frenzy created an unsustainable bubble. While the historic stock market crash of October 1929 occurred nearly eight months after he left office, many historians argue that his administration's policies directly set the stage for the collapse. The boom he oversaw ultimately became the bust that his successor, Herbert Hoover, would have to confront.