pyramid scheme
— Navneord
– Engelsk
～ a fraudulent scheme in which people are recruited to make payments to the person who recruited them while expecting to receive payments from the persons they recruit; when the number of new recruits fails to sustain the hierarchical payment structure the scheme collapses with most of the participants losing the money they put in
pump-and-dump scheme
— Navneord
– Engelsk
～ an illegal scheme for making money by manipulating stock prices; the schemer persuades other people to buy the stock and then sells it himself as soon as the price of the stock rises