What is "proprietary trading"

n. (context finance English) trade activity conducted by a securities firm for its own profit rather than for its clients.

Proprietary trading (also "prop trading") occurs when a trader trades stocks, bonds, currencies, commodities, their derivatives, or other financial instruments with the firm's own money, as opposed to depositors' money, so as to make a profit for itself. Proprietary traders may use a variety of strategies such as index arbitrage, statistical arbitrage, merger arbitrage, fundamental analysis, volatility arbitrage or global macro trading, much like a hedge fund. Many reporters and analysts believe that large banks purposely leave ambiguous the proportion of proprietary versus non-proprietary trading, because it is felt that proprietary trading is riskier and results in more volatile profits.