NEW YORK–(BUSINESS WIRE)–Kroll Bond Rating Agency (KBRA) assigns preliminary ratings to twenty-one classes of mortgage pass-through certificates from J.P. Morgan Mortgage Trust 2018-6 (JPMMT 2018-6), a prime RMBS transaction. JPMMT 2018-6 contains both prime jumbo (40.8%) and conforming (59.2%) collateral to borrowers with prime attributes. The JPMMT 2018-6 mortgage pool is composed of 1,678 first-lien mortgage loans with an aggregate principal balance of $938,152,649 as of the cut-off date.