To learn about how the antitrust agencies are challenging mergers and acquisitions, see our April cover story.

The antitrust agencies recently saw two changes in leadership.

Bill Baer was confirmed Dec. 30, 2012, as assistant attorney general for the Department of Justice's (DOJ) Antitrust Division. Previously Baer was in private practice and also had several stints at the Federal Trade Commission (FTC), including one as director of the Bureau of Competition from 1995 to 1999.

Claudia Higgins, who spent two decades at the FTC, most recently as assistant director for regional litigation, worked there with Baer and says he knows how to balance business with law.

“Bill Baer is someone who really does understand how to litigate, and he's somebody who understands the business side of things,” says Higgins, now a partner at Kaye Scholer. “Some might say that because he filed two cases in his first month it means that he's going to be a gangbuster at the DOJ, but it's going to be fairly balanced. He does come with really strong credentials in understanding both sides of the fence.”

At the FTC, Edith Ramirez took over from Jon Leibowitz as chairman in March. Leibowitz left on a high note in the wake of a Supreme Court victory and the conclusion of the agency's Google Inc. investigation.

Robby Robertson, former chief trial counsel for the FTC's Bureau of Competition and now a partner at Hogan Lovells, says that though the DOJ went through a period of risk aversion, the FTC has not operated that way, at least not since Tim Muris became chairman in 2001. Recent FTC successes in merger enforcement came after a string of losses and reflect the agency's persistence, Robertson says.

“Across the whole agency, not just on the competition side but on the consumer protection side, too, they take on what they believe is the right case, and they do it no matter what the risk is,” he says. “It's something that I would expect Edith Ramirez to continue—she's a bright lawyer who is not shy and is not afraid to take on risk.”