Allen & Overy New York senior partner Dan Cunningham (pictured) has defected to US litigation powerhouse Quinn Emanuel Urquhart Oliver & Hedges.

Dan Cunningham

The corporate partner, who has played a pivotal role in developing A&O’s New York office since joining the magic circle firm from Cravath Swaine & Moore in 2001, will start at Quinn Emanuel on 1 July this year.

Cunningham will provide Quinn Emanuel with a range of corporate skills. He will also lend his considerable knowledge of structured finance matters to the litigation boutique at a time when disputes relating to these financial products is on the rise.

Cunningham is well known for securing the International Swaps and Derivatives Association as a core relationship client for Allen & Overy. Since 1984 he has been involved in developing the ISDA documentation for derivatives transactions.

Quinn Emanuel New York head Peter Calamari said: “This is somewhat of an experiment for us. While Dan is not a litigator his expertise in complex financial instruments is very valuable to us. He will be working with our complex financial products team as well as the restructuring group.”

The firm’s managing partner John Quinn added: “Daniel’s addition to our firm does not signal that we are abandoning our litigation-only model. A very significant part of our practice is litigation involving complex, derivatives, swaps and other structured financial products. There are probably less than five lawyers in the world who have the expertise Daniel has in these areas.”

Cunningham was previously a partner at Cravath where he was head of the firm’s London office from 1990 until 1993. His 2001 move to A&O stunned the New York market at the time as he was seen as the first partner ever to leave a white-shoe firm for a UK rival.

An A&O spokesperson said: “We’d like to thank Dan for the extraordinary contribution he has made to Allen & Overy over the past eight years and wish him all the best for the future. His legacy at Allen & Overy includes transforming our New York office into a formidable competitor with the existing top New York firms, and personally building our leading corporate and M&A practice and a market-leading derivatives practice in New York.”