CHICAGO--(BUSINESS WIRE)--Fitch Ratings has affirmed nine classes of FREMF 2012-K21 multifamily commercial mortgage pass-through certificates series (FREMF 2012-K21) and Freddie Mac structured pass-through certificates, series K-021. A detailed list of rating actions follows at the end of this press release. KEY RATING DRIVERS The affirmations reflect the stable performance of the pool since issuance. There are no specially-serviced or delinquent loans in the pool. Multifamily properties repres