TOPEKA, Kan. (AP) — Kansas regulators on Wednesday rejected the proposed sale of the state's largest electric company to a Missouri firm, concluding that the $12.2 billion price was too high and would leave the combined utility financially weaker than the separate companies.

The Kansas Corporation Commission issued its order against a proposal from Kansas City, Missouri-based Great Plains Energy Inc. to buy Topeka-based Westar Energy Inc. after consumer advocates and the commission's own staff criticized the acquisition. Opponents argued that Great Plains was paying far too much and regulators...