One of the founders of the A Bank has moved on to Plan B. On Friday, Amegy Bank announced that Paul Murphy, its chief executive, was quitting the institution he helped start in 1990, effective immediately. Murphy has joined a Wall Street-backed investment group that plans to buy banks in other parts of the country, Amegy chairman Walter Johnson said. He'll remain on Amegy's board since the new venture won't directly compete. By Monday, Murphy was already on a roadshow, drumming up investor capital for his new venture. He said he isn't ready to give any details about his second act yet but stressed that his departure wasn't the result of any disagreements with Amegy or its parent company, Salt Lake City-based Zions Bancorporation. It's a theme that Johnson, Murphy successor Scott McLean and another co-founder, Executive Vice President Steven Stephens, also stressed in a meeting with me Monday morning at Amegy's offices. They talked up the benefits of selling Amegy to Zions four years ago and the 40 percent growth Amegy has enjoyed since then. Everyone, it seems, is happy. Perhaps a little too happy. The abruptness of Murphy's departure and the full-court reassurances of the remaining Amegy executives hint at more to the story. First of all, Zions may have been good for Amegy, but it's been a disaster for Amegy's investors. Those who got Zions stock in the 2005 takeover have watched shares plunge from almost $76 to less than $14, a slide under way well before the past year's banking crisis. Zions has struggled because of its exposure to West Coast markets, taking significant write-downs and tapping $1.4 billion in federal bailout funds, which it hasn't repaid. In other words, Amegy, which is among the strongest performers in Zions' stable of banks, may be doing more for Zions than Zions is doing for Amegy. Johnson and Murphy both dismissed rumors that either of them had approached Zions about buying Amegy back. If they didn't, perhaps they should have. As for Murphy, he joins an increasingly crowded field of equity investors hoping to capitalize on troubled banks. Big-name players such as Wilbur Ross, Paulson & Co. and the Carlyle Group have all made overtures for failed or failing banks, so Murphy's new firm will face well-heeled competition. Even so, the government has been reluctant to allow such deals. The Federal Deposit Insurance Corp. restricts ownership by private equity firms to no more than 10 percent of a failed bank and prohibits multiple firms from working in concert. 'The FDIC doesn't want some private equity firm that has a short-term time horizon to be an owner of community banks,' said Dan Bass, managing director of the Houston investment banking firm Carson Medlin Co. 'They need people that are in it for the long term.' Murphy would say only that he hopes 'to take what's happening in other parts of the country and make something positive of it.' He promised to share more details in a month or so when he can talk more freely. Across the country, banks the size of Amegy and Zions are finding it difficult to keep executives. Bad loans, increased regulatory scrutiny, stagnant growth and federally mandated pay restrictions have left many vulnerable to smaller institutions and investment groups looking to poach top talent. 'Paul has a great opportunity,' Johnson said. 'This is a big deal. It's very flattering for him, and it's very flattering for us.' Flattery aside, Murphy may have simply felt he needed a new challenge and recognized that, as McLean pointed out, the volatility in the banking industry creates an opportunity. But the smiles on Monday morning didn't quite dispel the unanswered question: Is that challenge so compelling that Murphy would chuck his beloved A Bank for Plan B? loren.steffy@chron.com blogs.chron.com/lorensteffy/. 