Sidley Austin LLP, formerly known as Sidley Austin Brown & Wood LLP, is the sixth-largest U.S.-based corporate law firm with 1900 lawyers, annual revenues of more than one billion dollars, and offices in 19 cities worldwide, with the most recent addition of Century City, in Los Angeles, in 2015. It is a full-service law firm, with broad experience in transaction and litigation matters. Its original predecessor firm was founded in 1866 and had former first lady Mary Todd Lincoln, then the widow of President Abraham Lincoln, among its earliest clients. The firm was formed as the result of the merger of two firms: the Chicago-based Sidley & Austin, founded in 1866, and the New York-based Brown & Wood, founded in 1914. The merger was completed in May 2001. The firm's headquarters is at One South Dearborn in Chicago's Loop.
In each year since the survey's inception, Sidley has received more First-Tier National Rankings than any other U.S. law firm in the Best Law Firms Survey by U.S. News & World Report. The 2015 US News Survey also named Sidley as the "Law Firm of the Year" in International Trade and Finance Law as well as Litigation – Securities. As of 2014, it was the 13th largest law firm in the world (and 8th in the US) by revenue. (Source: Wikipedia)