NEW YORK--(BUSINESS WIRE)--Kroll Bond Rating Agency (KBRA) assigns preliminary ratings to forty-four classes of mortgage pass-through certificates from WinWater Mortgage Loan Trust 2015-4 (WIN 2015-4), a prime jumbo RMBS transaction. The underlying WIN 2015-4 mortgage pool comprises 544 first-lien, residential loans with an aggregate principal balance of $405,005,648 as of the cut-off date. WIN 2015-4 is the eighth transaction for WinWater Home Mortgage, LLC, a new mortgage conduit formed in 20