Ponzi scheme

「ねずみ講」は英語で"pyramid selling/sales"とか"multilevel marketing/sales"と表現できるとガイド試験の受験勉強で覚えましたが、"Ponzi scheme"あるいは"Ponzi selling"という実在した詐欺師から来た名称もある事を知りました。
any fraud that pays quick returns to early investors with money sucked from latecomers as a "Ponzi scheme"
以下はメルマガArcaMax Vocabularyからの引用です。
In 1919, Charles Ponzi, an inveterate con man, devised a new form of fraud. He sold promissory notes to investors, guaranteeing them a 40 percent return over a short time period.
As Ponzi recruited new participants, he used their money to pay dividends to the first investors. This made his gimmick seem legitimate, luring even more people who were eager to get in on the action.
All along, of course, Ponzi was pocketing oodles of money for himself, and soon he was sporting expensive suits and gold-handled canes. But, as the number of participants multiplied, he could no longer pay off all the investors.
Within a short time, the whole scheme crashed, thousands of investors lost their money and Ponzi was sentenced to federal prison.

英英辞書にあるpyramid scheme/sellingの説明です。 an illegal system of investing money,in which the money of people who invest later is used to pay people in the system who invested earlier
いずれにしても甘いもうけ話には気をつけましょう。