Fifth Third Bancorp (FITB) has agreed to purchase Dallas-based Comerica (CMA) for $10.9 billion, the regional banks said Monday. Pending regulatory approval, the deal would create the nation's ninth-largest bank, with$288 billion in assets. The all-stock transaction is aimed at helping Midwest lender Fifth Third, based in Cincinnati, compete against the nation's megabanks as it seeks to expand in the Southeast and Southwest. Comerica's stock rose 14% in early Monday trading. It's up just as much for th ...