http://finance.yahoo.com/news/facebook-market-makers-losses-total-024559525.html Curiously, the 4 firms mentioned in this article represent 4 of the 5 firms that compose the payment-for-order-flow oligopoly. I'm not sure it's right to call them "market makers" (even if they've got the designation) when their primary business is backdoor deals with the big retail brokers to squeeze an invisible $.001-$.002 per share from their customers. http://online.wsj.com/article/SB10001424052748704691304575254842975842532.html