The scheme is named after Charles Ponzi, who duped thousands of New England residents into investing in postage stamp speculation in the 1920s. But Ponzi is not the original mastermind behind the scheme; various reports show that there were several similar scams before he was born. (Charles Dickens’ 1857 novel “Little Dorrit,” for example, described such a scheme whereby the fraudulent dealings of Mr. Merdle led to the collapse of his bank.) Ponzi’s operation, however, took in so much money that it was the first to become widely known in the United States. Ponzi promised investors that he could provide a 50% return in just 90 days, at a time when the annual interest rate for bank accounts was 5%. Based on the arbitrage of international reply coupons for postage stamps, Ponzi quickly diverted investors’ money to support payments to earlier investors and to himself.

As originally designed, a Ponzi scheme remains a fraudulent operation that pays returns to separate investors, not from an actual profit earned but from the investors’ own money or money paid by subsequent investors. The scheme typically entices new investors by offering returns that other investments cannot guarantee, in the form of short-term yields that are either extraordinarily high or unusually consistent.
The main reason why the scheme initially works is that the early investors, those who actually got paid the large returns (from the investments of new entrants) reinvest their money in the scheme. Meanwhile, the fraudsters gain the investors’ confidence, maintaining the deception of high profits. Claims of a “proprietary” investment strategy, which must be kept secret to ensure a competitive edge, frequently is touted to hide the fraudulent operation.

The fraudsters also try to minimize withdrawals by offering new plans to investors, often freezing their money for a long time in exchange for higher returns. If a few investors do wish to withdraw their money in accordance with the strict terms, the requests are usually promptly processed, giving the illusion to other investors that the fund is solvent.

But once the required continuous stream of investors slows down, the scheme begins to collapse as the fraudsters start to have problems paying the promised returns (the higher the returns, the greater the risk of collapsing). Such liquidity crises often trigger panics, as more people start asking for their money, similar to a bank run. (A bank run, also known as a “run on the bank” occurs when a large number of customers withdraw deposits because they believe the bank is, or might become, insolvent.)

External market forces, such as the global economy decline in 2008, also cause many investors to withdraw part or all of their funds, not necessarily because of fraud suspicions, but simply due to underlying market conditions. (In Madoff’s case, the fund could no longer appear legitimate after investors attempted to withdraw $7 billion in late 2008.)

And of course, there is rarely a happy ending to this story as fraudsters attempt to vanish, taking the remaining investment money with them.