The market condition where a few buyers control the market for a product.[From Greek oligo- (few, little) + opsonia (purchase).]
A word that shares the same prefix is oligarchy: government by the few, where political power is held by a small group and used for selfish and corrupt purposes.
"Does a joint Internet venture by the world's automakers to purchase parts amount to an illegal oligopsony--a cartel of buyers that can drive prices down through their market power?"
James V. Grimaldi; Trustbusters Put On a Stern Face; The Washington Post; Jun 29, 2000.
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