Elite Manhattan firms Simpson Thacher & Bartlett and Skadden Arps Slate Meagher & Flom have taken lead roles on Mars' merger with rival confectionary group Wm Wrigley Jr Co – one of the largest M&A deals of the year so far.

The deal – worth approximately $23bn (£11.5bn) – sees Simpson Thacher client Mars acquire Wrigley, with Warren Buffet's Berkshire Hathaway investment group taking a $2.1bn (£1.05bn) stake in Wrigley.

New York M&A partners John Finley and Kathryn Sudol took the lead for Simpson Thacher advising Mars.

Skadden acted on behalf of Wrigley, with the firm fielding a Chicago-based team that included client relationship partner William Kunkel and fellow corporate partner Byron Vance.

In 2005 Kunkel advised Wrigley on its acquisition of Kraft Foods' sugar confectionary business in a deal valued at around $1.5bn (£750m).

Paul Hastings Janofsky & Walker also landed a role on the latest deal, acting for financial adviser JP Morgan. New York corporate partner Charles Baker led the team for the US firm.

Mars is the world's largest maker of chocolate, with a global market share of around 15%. The combined group will have annual revenues of around $27bn (£13.5bn).

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