A New York litigation boutique that represents high-profile clients, such as a fired Trump administration cybersecurity official and a Russian doping whistleblower, has opened a Philadelphia office and is in talks with lawyers along the East Coast for other potential offices.

Co-founder Jim Walden, formerly of Gibson, Dunn & Crutcher, opened Walden Macht & Haran in 2015 with just six lawyers. The firm now has 42, including 11 partners. Earlier this year the firm signed a new lease for more office space in New York, and it is scoping out potential expansion into Washington, D.C., and Wilmington, Delaware—another example of a growing litigation boutique competing with big firms for talent and business.