NEW YORK--(BUSINESS WIRE)--Fitch Ratings has placed the 'BBB+' Issuer Default Rating (IDR) of Black Hills Corporation (BKH) on Rating Watch Negative following the announcement of a definitive agreement to acquire Source Gas Holdings LLC (SGH, not rated by Fitch) from investment funds managed by Alinda Capital Partners and GE Energy Financial Services. In addition, Fitch has affirmed the IDR of BKH's wholly-owned regulated electric utility subsidiary, Black Hills Power, Inc. (BHP) at 'BBB+' with