NEW YORK--(BUSINESS WIRE)--Kroll Bond Rating Agency (KBRA) is pleased to announce the assignment of preliminary ratings to three classes of the BAMLL 2015-ASTR securitization, a $273.5 million CMBS single borrower transaction (see ratings list below). The collateral for the securitization consists of a single, non-recourse, first lien, fixed-rate mortgage loan that is secured by the borrower’s leasehold interest in 51 Astor Place, a 12-story, Class A, LEED Gold Certificate office building locat