The nation’s 350 largest law firms showed the biggest head count growth during 2013 since the nosedive of the recession years, with a respectable 3.9 percent increase. The percentage change in Washington wasn’t quite that robust—2.4 percent—but a gain nonetheless. Yet the upswing was not quite the testament to a rebounding U.S. legal market it might seem. Almost all of the boost came from a flood of foreign lawyers to big U.S.-based firms through international mergers.

Last year, Fulbright & Jaworski completed its combination with London-based Norton Rose to create Norton Rose Fulbright, ranked No. 3 on this year’s list. SNR Denton merged with European firm Salans and Canada’s Fraser Milner Casgrain to form Dentons, ranked No. 4. And K&L Gates continued its march around the globe by combining with Australia’s Middletons.