Yes, and this: How Quote Levels Are Used All bro
Post# of 85482
Quote:
How Quote Levels Are Used
All brokerages and financial institutions have best execution requirements on behalf of their customers. This means that they are required to provide their customers with the best stock price currently available. If a private investor, for example, wants to invest in Apple stock, they would see the level I bid and ask prices listed on their broker's online trading portal.
When the customer initiates an order to purchase the stock, the broker uses level III quotes to give that investor the best possible price. So the deeper information contained in level III quotes is used to the benefit of the investor, even though they are only seeing level I quotes.
I see how this could be abused.