Quote from BankBank:
prop trading is, very simply, taking positions in the market using someone else's money. usually a bank's. goldman hires prop traders. they employ prop traders.
many banks, even very small ones, have prop trading. frequently, the prop trades are an activity done on the side, with the trader's primary responsibility being fulfilling customer orders or squaring the bank's position.
i would hazard a guess that the vast majority of real prop trading is done in rates, credit, and fx, and not equities.
putting up money to day-trade is not prop trading. period.
Isn't this what I said?

