I take back what I said. I was mistaken.
Virtu made 1.8Bn T12M and earned 300MM in operating profit (about 15%)
GS made 35Bn T12M and earned 13Bn in operating profit (40%ish)
MS is in the 30% range for operating income
Greenhill and PJT are in the 20% operating profit margin (you would think it would be higher given that it's all fees and costs are airplane tickets, paper, and banker comp).
Virtu has also executed several M&As, and has been overhauling KCGs old platform, which I suspect is a hurting their margins.
Virtu also only has ~150 employees. $2M per employee PROFIT is pretty good! Compare that to $350K for Goldman