Washington, D.C.-born Covington & Burling believes one of the secrets behind its 25-year growth trend lies in its collaborative business model.

According to ALM data, except for a 0.3% drop between 2010 and 2011, Covington has experienced uninterrupted year-over-year growth since 1996. All told, the firm has grown 1,140% in the past quarter-century.