Business owners may worry that one drawback of signing up with a de novo bank is that it's built to flip. And in some cities, there are already well-known serial bank entrepreneurs. Of course, any business you work with can be sold at any time. But according to the FDIC, only 5% of de novo banks are acquired in their first five years of business. Meanwhile, more de novos are chartered every week. Consider the extraordinary case of Square 1 Bank, based in Durham, N.C., which was formally established last August. Initially, a group led by CEO Richard Casey set out to raise $105 million, the amount specified in its charter and an unusually large sum for a de novo bank. In fact, the offering was oversubscribed at $200 million. Like other de novos, Square 1 was set on course by a merger. Casey had been an executive at Imperial Bank, where he initiated a program for lending to venture capital-backed companies. Imperial was then taken over by Detroit-based Comerica Bank. Casey left after ...