NEW YORK--(BUSINESS WIRE)--Kroll Bond Rating Agency, Inc. (KBRA) assigns preliminary ratings to twenty classes of mortgage pass-through certificates from Agate Bay Mortgage Trust 2015-6 (ABMT 2015-6), a prime jumbo RMBS transaction. The underlying ABMT 2015-6 mortgage pool comprises 401 first-lien, residential loans with an aggregate principal balance of $310,388,850 as of the cut-off date. ABMT 2015-6 represents the tenth RMBS transaction sponsored by TH TRS Corp. (a subsidiary of Two Harbors