Any bank will provide it's buy side customers research and in many cases software or at least web applications to evaluate and price securities which are over t

Any bank will provide it's buy side customers research and in many cases software or at least web applications to evaluate and price securities which are over the counter and/or illiquid. It's not just courtesy; it's necessary if you want to buy and sell the stuff. However, a customer who blindly puts their trading book onto some Goldman application isn't smart enough to do business with Goldman. As someone who worked at a large bank providing month-end marks for customers (as a 'courtesy'), we knew that we were basically just seeing the stuff we had sold them, and at most half of any other positions they asked for were actually bonds they owned.