You are probably right, somewhere in between, But right now the prop guys can't trade, so I wonder why Assent would be willing to lose them. Was it a compliance issue?
Don't thinks so about the compliance. From what I heard many of the prop guys would rather focus on trading these other products instead of stocks so I don't think most of the traders were that concerned about losing stocks, although that might not be the case with all of them. Assent could have pulled their prop deals (if that is true) because they were not receiving any revenues from these other products and there was not much volume being traded their anyway in stocks. Just a guess though (once again assuming that above is true).