[[Trillium engaged in a ârepeated pattern of layering conduct to take advantage of trading, including algorithmic trading by other firms,â Finra said. The company did this by submitting bids or offers designed to induce other traders to raise or lower prices and then executing trades on the opposite side of the market at better levels than would otherwise have been available, according to the regulator.]] Basically, the prop firm front-runs the front-runners like GS. This is like playing chess: You anticipate what GS and other front-runners will do to your orders, and send your fake orders out, make the front-runners act, then you withdraw your orders and tell GS: you just got deceived! hahahhahahaha! Of course, GS and other powerful wall street firms are not amused and they complain to SEC that some prop firm has the guts to deceive them. "How dare they!!!" said Mary Shapiro, "They deceive my friends at GS??? They must be out of their mind! I am going to punish them for taking money from GS!!!" So SEC fines the prop firm for front-running the front-runners.