Two firms that showed strong gains in 2011—Arnold & Porter and Baker & Hostetler—benefited from active practices involving special investigations. Baker & Hostetler is best known these days for its work on the liquidation proceedings of Bernard L. Madoff Investment Securities, which contributed to a 14 percent increase in gross revenue and 10.5 percent rise in profits per partner. Arnold & Porter, which saw growth in several practice areas that include investigative work, posted a 15 percent rise in gross revenue. And its 25 percent profits per partner boost is the biggest increase of any Am Law 100 firm.

Arnold & Porter chairman Thomas Milch acknowledges that building a practice around special investigations can be unpredictable. “It’s a little bit more of a leap of faith,” he says. “It’s less obvious that you’ll know where the work is coming from. In patent work, for example, you often can count on repeat work. In government investigations, it’s more one-off matters.” These assignments also require special teamwork, bringing together lawyers with varied specialties and backgrounds. “You have to work with other law firms well, too,” he says. Arnold & Porter is one of several firms, including Kirkland & Ellis and Wilmer Cutler Pickering Hale and Dorr, that are coordinating on Deepwater Horizon matters for BP p.l.c.