proprietary tradernoun [ C ]
ukusalso prop trader STOCK MARKET, FINANCEan employee of a financial organization who uses the organization’s money to trade in shares, stocks, bonds, etc. in order to make a profit for the organization rather than for its customers:
The proprietary traders traded company money to increase bank profits and their own paychecks.
A prop trader at Deutsche Bank lost $1.8bn in 2008.