Because the firm is technically "at risk" on the block of stock (if the price of the stock drops below the price at which the block was purchased, the firm will be at a loss on the stock) and stock is usually sold at or even slightly below the then-current prevailing market price offer/ask, the practice is still legal in the United States. In fact, it is not required that this profit spread be disclosed to the client, since it is not technically a "commission". When a securities dealer sells such instruments from its own inventory, a client will receive a trade confirmation stating the transaction was done as "Riskless Principal" or "Markup", which in fact, just like commissions, is also revenue to the firm, and such a practice is often subject to abuse. Only the amount of fees charged over and above the offer/ask are commissions, and must be disclosed. But even though it is still legal, it is frowned upon by the Securities Exchange Commission, and they are using other laws and methods of attack to indirectly thwart