A quartet of former senior federal lawyers from the US Federal Trade Commission and the Department of Justice have launched a plaintiff law firm focused on antitrust litigation.

The new firm – Simonsen Sussman – is led by former FTC lawyers Catherine Simonsen, Shaoul Sussman and Nicolas Stebinger, and former DOJ attorney Kate Brubacher. The firm says it intends to combat “the worst abuses of corporate power in our economy” by helping entrepreneurs, new entrants, small businesses, workers and other victims of unfair practices and violations of competition laws.

Simonsen said: “Antitrust law is at a significant inflection point. Courts, enforcers and practitioners increasingly recognise that large corporate interests have gone too far in watering down our statutes, stifling competition and harming small businesses.”

Simonsen, who will serve as Los Angeles managing partner, spent a year at the FTC before leaving in January amid wider cut backs from the Trump administration. She previously spent two years in the California DOJ as deputy attorney general for antitrust. Prior to that she spent almost five years at White & Case, becoming a partner in 2021. She also spent almost four years at Perkins Coie.

Sussman will serve as managing partner of the firm’s founding and principal office in New York. He spent more than three years at the FTC, becoming an associate director in 2022 before leaving earlier this year. Prior to his time at the FTC, he was an associate at Pearl Cohen.

Stebinger will be managing partner of its Washington DC office. He spent close to six years at the FTC, most recently as deputy chief for the criminal liaison unit until his exit in January. Prior to his time at the FTC, Stebinger was an assistant public defender in Florida and a law clerk for judge James Cohn in the US District Court for the Southern District of Florida. He started his career in private practice at Chadbourne & Parke.

He said: “Through aggressive, targeted investigation, we intend to bring suits closer-in-time to when harm has occurred. We are nimble enough to take cases that would be infeasible for government enforcers. And because we will not face the same institutional constraints, we can forcefully make the most persuasive arguments on behalf of each and every client.”

Brubacher, meanwhile, will head up the firm’s Midwest office, having spent the past two years as a US attorney for the District of Kansas. Prior to that she spent six years as an assistant prosecuting attorney in Jackson County. She started her career in private practice at Cravath Swaine & Moore before moving to Cooley, where she spent five years in its New York office.