As more national law firms expand in Washington, D.C., and grow their regulatory credentials, homegrown law firms in the region are facing stiffer competition to land on the largest investigations and to advise big corporations about government regulations.

Sidley Austin, Morgan, Lewis & Bockius and Latham & Watkins are now among the 10 largest firms by head count in D.C., according to ALM data, competing with firms founded in the district, such as Crowell & Moring, Arnold & Porter Kaye Scholer, Covington & Burling, Steptoe, ArentFox Schiff and Venable.