what is proprietary trading

自营, 业主帐户交易 (指交易成员在其自身帐户上, 而不是为客户进行的交易. 这种交易应记入交易所的帐户上)

投资银行为获取利润而从事的股票，债券或其他交易。

百科全书+个人理解

Proprietary trading (also "prop trading" or PPT) occurs when a firm trades stocks, bonds, currencies, commodities, their derivatives, or other financial instruments, with the firm's own money as opposed to its customers' money, so as to make a profit for itself.