Westar Energy Inc. has agreed to be acquired by Great Plains Energy Inc. (GPE) for $8.6 billion plus the assumption of Westar's debt. The transaction is expected to close by mid-2017. We are affirming our ratings on Westar and subsidiary Kansas Gas&Electric Co. (KGE), including the 'BBB+' issuer credit ratings, and revising the outlook to negative from stable. The negative outlook reflects the potential for lower ratings on Westar, after the merger closes, if the combined entity's financial performance weakens such that funds from operations to total debt is consistently less than 13% after 2018. On May 31, 2016, S&P Global Ratings affirmed its ratings on integrated electric utilities Westar Energy Inc. and subsidiary Kansas Gas&Electric