This week, the [Justice] department sent a letter to the Federal Reserve and the Office of the Comptroller of the Currency saying it had concluded its investigation and did not believe there were concerns that warranted blocking the deal,...The department does not have direct authority to approve banking deals, but it can sue to block them. The Federal Reserve and comptroller could still block the deal, but the new legal analysis is significant because analysts had expected the Justice Department to be the most likely of the three agencies to object. Federal banking agencies have not formally denied a bank merger application since 2003, according to Jeremy Kress, a professor of law at the University of Michigan business school.

​​​​​​Capital One, with $479 billion in assets, is the nation’s ninth largest bank. Acquiring Discover would give it access to a credit card network of 305 million cardholders, adding to its base of more than 100 million customers.