Simpson Thacher & Bartlett antitrust head and former Clifford Chance (CC) rainmaker Kevin Arquit is leaving the firm to join Weil Gotshal & Manges.

Arquit, who has been at Simpson Thacher since joining from CC in 2002, will co-lead his new firm's global antitrust practice alongside former CC 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 formerly worked together at US firm Rogers & Wells, which merged with CC in 2000. The duo, who were appointed as global co-heads of CC's antitrust practice following the merger, were compensated as 'super-plateau' partners at the magic circle firm, with 300 and 275 equity points, well ahead of the plateau of 100 points at that time. Arquit was reputed to have been bringing in £40m of business annually.

Following the troubled merger, Arquit left CC in 2002 for Simpson Thacher, while Newborn left CC in 2003 for Weil, where five of the pair's former Federal Trade Commission colleagues are now partners.

"This originated by virtue of two very close personal friends and close professional colleagues," said Wolf, who 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.

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 on the cigarette maker's $27.4bn sale in 2014 to Reynolds American. Arquit also advised DirecTV that same year on antitrust matters related to the satellite television operator's $48.5bn sale to AT&T.

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, JPMorgan Chase, KKR and The Blackstone Group.

Simpson Thacher rarely loses partners but in 2014, executive compensation expert Andrea Wahlquist decamped for Wachtell Lipton Rosen & Katz. Last year, the firm saw Sidley Austin recruit its Los Angeles leader Daniel Clivner, while Kirkland & Ellis returned to the firm in March for M&A partner Peter Martelli in New York, its third partner-level hire from Simpson Thacher in three years.

Leiming Chen, a capital markets partner at Simpson Thacher in Hong Kong, also left earlier this year to become general counsel at long-time firm client Alibaba Group Holdings' 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 DC.