A type of investment fraud in which investors are promised artificially high rates of return with little or no risk; original investors and the perpetrators of the fraud are paid off by funds from later investors, but there is little or no actual business activity that produces revenue. The scheme generates funds for previous investors so long as there is a consistent flow of funds from new investors. This gives the impression that the earlier investments drastically increased in value in a short period of time. The scheme inevitably collapses when too many investors demand redemption or when the scheme fails to attract a sufficient number of new investments. The Ponzi scheme is named after Charles Ponzi, who in the 1920 defrauded thousands of investors in Boston.