Cadwalader Wickersham & Taft's energy and commodities group is breaking up, with lawyers leaving for Allen & Overy (A&O) and Haynes and Boone, in a process that will see the US firm close a Houston office that it opened six years ago.

The departures include Washington DC partners Gregory Mocek and Anthony Mansfield (pictured above), who are joining A&O's US investigations and litigation practice.

The two were once part of a high profile energy group that joined Cadwalader in 2011 from McDermott Will & Emery. Mocek, a former director of enforcement at the US Commodity Futures Trading Commission (CFTC), headed McDermott's energy and commodities practice and enforcement defence team. Mansfield once served as chief trial attorney and counsel to Mocek at the CFTC and was a member of the energy and commodities groups at McDermott and Cadwalader.

"With extensive global reach and deep connections to the relevant industries, A&O is well positioned for global commodities investigations and enforcement actions," said partner John Terzaken, who heads A&O's investigations and litigation group in Washington DC. "Adding partners like Greg and Tony, both with deep CFTC experience, to our team will provide our clients the support they need to manage the growth of multi-billion-dollar, multi-jurisdictional enforcement actions."

The hires for A&O come after the firm last year added five leveraged finance partners in New York by recruiting laterals from Milbank Tweed Hadley & McCloy, Proskauer Rose and White & Case. (Milbank returned the favour in November by hiring three A&O partners in New York, including the firm's former US leader).

Cadwalader managing partner Patrick Quinn said the firm's decision to shut its Houston outpost was a reflection of its new emphasis on a core client base that includes big banks and financial institutions, large companies and hedge funds.

"This focused strategic approach has, not surprisingly, resulted in some of our partners moving on," Quinn said. "We are sad to see our friends depart and wish them well. However, in order to provide exceptional service to our natural client base and a profitable platform for our partners, we must continue to pursue our strategy."

Last September, Cadwalader also announced the closure of its Asian offices in Beijing and Hong Kong. In recent weeks, firms such as Jones Day, King & Wood Mallesons, Latham & Watkins and Stephenson Harwood have moved to pick up Cadwalader refugees from those offices. The American Lawyer reported last summer that Cadwalader had held merger talks with King & Spalding and a small New York litigation firm.

The American Lawyer also reported last week on the departure of Cadwalader partners Paul Pantano and Athena Eastwood for Willkie Farr & Gallagher in Washington DC. Both lawyers were part of the energy team that Cadwalader hired from McDermott six years ago, as was partner Doron Ezickson. The latter was initially based in London, where he used to head McDermott's office in the city and led the firm's international energy and commodities practice. At Cadwalader, Ezickson established the firm's UK energy and commodities practice before returning to the US to serve as senior counsel in its energy and commodities group in Washington DC.

Last week, the Anti-Defamation League announced that it had hired Ezickson as a regional director in the nation's capital. The New York-based non-profit seeks to fight anti-Semitism and secure justice for Jewish people around the world.

Cadwalader's energy group was hit hard in February 2015 when Sidley Austin recruited four partners in Houston and Washington DC, all of who joined the firm as part of the move from McDermott in 2011. Michael Niebruegge, a former Cadwalader energy finance partner in Houston, also resurfaced that same month at Willkie Farr. In an effort to offset those losses, in March 2015 Cadwalader hired Sutherland Asbill & Brennan energy transactional partner Chad Mills in Houston.

However, Mills is now set to join US firm Haynes and Boone with special counsel Adam Roth and associate Kathryn Shurin, both of whom are based in Houston.

The closure of Cadwalader's Houston operations leaves it with offices in Brussels, Charlotte, North Carolina, London, New York and Washington DC. The firm has said it remains committed to serving clients from its two European outposts, although its Brussels base has just one remaining partner after the departure of a four-lawyer antitrust team last week for Dechert.

Quinn, who took over as Cadwalader's leader two years ago this month, noted that his firm recently made up 10 lawyers to partner, its largest new partner class since 1993. Last year, Cadwalader brought back former partner Jason Halper from Orrick Herrington & Sutcliffe to co-head its litigation group and forged an alliance with French restructuring boutique Bremond & Associes.