Simpson Thacher & Bartlett antitrust partner Kevin Arquit will join Weil, Gotshal & Manges as of Jan. 1, 2017, the latter announced Tuesday.

Arquit, who served as head of Simpson Thacher’s antitrust group, will co-lead his new firm’s global antitrust practice alongside his former partner and Federal Trade Commission colleague Steven Newborn, Weil’s current antitrust head.

“We believe we already had the number one destination antitrust practice,” said Weil executive partner Barry Wolf. “With Kevin’s addition, no one, I think, will doubt that.”

Arquit and Newborn served at the FTC together, where Arquit was general counsel and director of its Bureau of Competition and Newborn served as the Bureau of Competition’s director of litigation. Arquit left the FTC in 1992 for Rogers & Wells, while Newborn left the regulator two years later for the New York-based firm. Rogers & Wells merged with Clifford Chance in 2000, and Newborn and Arquit became the highest-paid partners at the Magic Circle firm, according to our previous reports.

Following the troubled merger, Arquit left Clifford Chance in 2002 for Simpson Thacher. Newborn left Clifford Chance in 2003 for Weil, where five of the pair’s former FTC colleagues are now partners. Arquit, 62, was unavailable for comment Tuesday evening about his decision to re-join Newborn at Weil.

“This originated by virtue of two very close personal friends and close professional colleagues,” Weil’s Wolf said in a phone interview.

Wolf insisted that his firm’s recruitment of Arquit was not about bringing on new clients, but building up Weil’s existing antitrust group.

“If every matter stays at Simpson Thacher, that’s fine with us,” Wolf said, adding that Weil is bringing on Arquit for his reputation as one of the field’s leading experts.

Weil partners recently voted to add Arquit to their partnership and the firm informed the rest of its lawyers and staff Tuesday evening about his move. Wolf said it remains unclear how the new administration of President-elect Donald Trump will approach antitrust, after strong enforcement under President Barack Obama.

“We see a booming M&A market, so we see more antitrust happening because the M&A activity will be robust,” Wolf said.

Arquit, who spoke with The American Lawyer earlier this year about the antitrust landscape, served as antitrust counsel to Lorillard Inc. on the cigarette maker’s $27.4 billion sale in 2014 to Reynolds American Inc. Arquit also advised DirecTV that same year on antitrust matters related to the satellite television operator’s $48.5 billion sale to AT&T Inc.

Arquit’s antitrust group at Simpson Thacher won The American Lawyer’s antitrust litigation department of the year award in 2014 for its role in class actions against Fidelity National Financial Inc., JPMorgan Chase & Co., KKR & Co. LP and The Blackstone Group LP.

Simpson Thacher, which did not immediately return a request for comment about Arquit’s departure, rarely looses partners. But in 2014, exeutive compensation expert Andrea Wahlquist decamped for Wachtell, Lipton, Rosen & Katz. Last year the firm saw Sidley Austin snag its Los Angeles leader Daniel Clivner, while Kirkland & Ellis added M&A partner Peter Martelli in March. Kirkland returned to Simpson Thacher in late October for antitrust partner Matthew Reilly in Washington, D.C. Reilly is a former assistant director at the FTC.

Leiming Chen, a capital markets partner at Simpson Thacher in Hong Kong, also left earlier this year to become general counsel at longtime firm client Alibaba Group Holdings Ltd.’s Ant Financial Services Group. In August, Simpson Thacher made a notable lateral raid of its own, recruiting financial institutions partner Keith Noreika from Covington & Burling in Washington, D.C.