Exclusive: Dewey rainmaker Mort Pierce set to quit for White & Case

The defection will be one of the most damaging departures yet to hit the struggling US firm.

Pierce, arguably the firm’s top M&A rainmaker, told The Lawyer that he could not yet comment, but it is understood that the move has been confirmed. He has not yet resigned.

Pierce is understood to be taking a team of between eight and 10 of his fellow New York corporate partners with him, with the move all but finalised.

The news comes as a team of three Dewey London partners - including managing partner Peter Sharp - are set to join Morgan Lewis & Bockius in London.

Sharp, who also led legacy firm LeBoeuf Lamb Green & McRae’s London office, will be joined at Morgan Lewis by fellow litigation partners David Waldron and Nick Greenwood.

In a statement, Morgan Lewis chair Francis Milone said: “Peter, Nick, and David have handled substantial and sophisticated disputes both in the UK and elsewhere in a number of key industry sectors in which the firm has many clients, including energy and financial services. Their experience representing companies and individuals around the world—from the UK to Europe, Asia, the Middle East, Africa, and the Caribbean—will be a tremendous asset to our multinational clients.”

Pierce’s exit will be a huge blow for the troubled Dewey, with the lawyer widely considered to be a legendary force within the firm. He was instrumental in driving the merger between Dewey Ballantine and LeBoeuf Lamb Greene & MacRae in 2007 (28 August 2007).

LeBoeuf chairman Steven Davis, who is currently under investigation by the Manhattan district attorney’s office (30 April 2012), also led the merger talks.

Pierce is a leading figure on Wall Street and a regular adviser to Deutsche Bank. In 2006 he told The Lawyer he was a workaholic who enjoyed the daily grind. “I’m a hard worker. I routinely bill between 2,900 and 3,400 hours. I’m a workaholic, I admit it,” he said, adding “the last time I looked that wasn’t a crime” (6 March 2006).

He advised Walt Disney on its $4bn (£2.46bn) acquisition of Marvel Entertainment (7 September 2009) and its deal to take over Pixar.

The recession, however, has hit his practice hard in New York. Pierce is believed to have suffered a 45 per cent drop in his deal rate in the past year (16 April 2012).

These most recent departures will take the number of partner exits from the firm in 2012 to around 100.

Dewey could not be reached for comment. White & Case declined to comment.