noun
pyramid scheme
A fraudulent investment scheme where participants recruit new members to pay earlier investors, named after the rapid multiplication of mice. Often used in legal and consumer warning contexts.
ねずみ講は法律で禁止されている。
Pyramid schemes are prohibited by law.
彼は友人にねずみ講に誘われたが断った。
He was invited by a friend to join a pyramid scheme but refused.
マルチ商法 (multi-level marketing) is a legal business model where income comes from product sales and recruitment, whereas ねずみ講 is an illegal pyramid scheme focused solely on recruitment fees.
無限連鎖講 is the formal legal term for pyramid schemes, often used in statutes; ねずみ講 is the common colloquial term.
Compound of ねずみ (mouse/rat) and 講 (association/group), referring to the rapid, mouse-like multiplication of participants in a pyramid scheme.