Fifth Third Agrees to Buy MB Financial

Deal for the Chicago-based regional bank is valued at $4.7 billion

Fifth Third Bancorp said Monday it has agreed to buy MB Financial Inc. in a mostly stock deal, further expanding Fifth Third’s presence in Chicago.

The deal didn’t appear to win over investors. The companies valued the transaction at $4.7 billion, though a sharp drop in Fifth Third’s stock pushed that value down. Analysts questioned the deal’s price tag, which is at a 24% premium to MB Financial’s value last Friday.

Fifth...