Which company founded by Charles Ponzi collapsed in the 1920 scheme that became a byword for fraudulent investment bubbles?

Charles Ponzi's Securities Exchange Company collapsed in 1920 after his fraudulent investment scheme unraveled.

Ponzi promised investors unusually high returns by claiming he could profit from differences in international reply-coupon prices. In reality, the operation used money from newer investors to pay earlier ones. The company attracted large sums in Boston before newspapers and financial investigators exposed contradictions in its claims.

The scheme collapsed after the Boston Post published investigations and authorities examined the company's finances. Ponzi was arrested in August 1920 and later convicted of mail fraud. His name became attached to the general term “Ponzi scheme,” even though similar frauds had existed before him. The episode is often discussed alongside stock-market crashes, but it was primarily an investment fraud rather than a broad exchange collapse like 1929 or 1987. The company's formal name is sometimes omitted in popular accounts, which refer simply to Ponzi's business or investment scheme.