Stock loan is one of the most profitable aspects of any major clearing firm. Since few clients really understand this cost, the clearing firms have been raping and pillaging investors for years. Are you familiar with single stock futures traded at OneChicago? It is a great idea, that is being held up by most major clearing firms. (IB is one of the good ones, BTW.) Go to this link:http://www.onechicago.com/?page_id=1289 Then scroll down to the product you would like to evaluate. The front month "efp bid" rate should be somewhere in the neighborhood of your short stock carry rate, and the front month "efp offer" rate should be close to your long stock rate. If your broker's short rate is consistently and significantly lower than the "efp bid" rate, then you know they are screwing you. (There used to be an easier way to find the implied rates of the market bid and offer prices, so I apologize if the above is not as user friendly as I would like.) The aren't very liquid and most clearing firms do not allow their customers to trade them, though IB is an exception. These products allow you to keep the delta risk of your stock while eliminating the need to borrow stock from your firm at a negative rate. It is probably only a good idea for the most knowledgable traders to use these highly illiquid products BUT anyone can go to the website to check on stock implied carrying rates. This should allow you to check your clearing firm's carrying costs. (It just so happens that the stock loan department of any major clearing firm is a $ multi billion business. It is my opinion that these profits are pure theft from the unknowing traders with stock positions.)