CBOE Holdings Inc., owner of the largest U.S. options exchange, is poised to acquire Bats Global Markets Inc., the nation’s second-largest stock exchange operator.

The $3.2 billion cash-and-stock deal, which was announced Monday and still requires the approval of shareholders and regulators, has yielded roles for at least three Am Law 100 firms. If completed, CBOE’s new president and COO will be Chris Concannon, a former Morgan, Lewis & Bockius associate currently serving as CEO of Bats.