If you search online for IGT form 8937 July 2015, you will find a document that gives you all the details you need.
I received two 1099-B forms. One was for the cash given per share and the cash-in-lieu of fractional shares, and the other was for the new shares converted. For the cash-in-lieu and the new shares, the FMV value was listed as $20.23, which is higher than the $20.08 shown in the form 8937. I am using the amount on the form 1099-B for the FMV to determine my cost-basis in the new shares. I had no losses, so thankfully I do not have to deal with that. From the research I've done, you are lucky to be able to claim any loss at all. Many mergers don't allow any loss to be recorded.