Allen & Overy (A&O) has sealed its largest-ever M&A deal in New York, bagging a lead advisory role for General Electric (GE).

The deal is a major boost to the magic circle firm's US corporate practice and comes after A&O advised GE on the US law sale of its low-margin materials unit to private equity house Apollo Management in a $3.8bn (£2bn) transaction.

On that occasion, corporate partners Dan Cunningham, Eric Shube and Peter Harwich led the A&O team, which also comprised lawyers from offices in Belgium, China, France, Germany, Japan, Singapore, Thailand and the UK.

Elite Manhattan firm Wachtell Lipton Rosen & Katz advised Apollo on the deal, with corporate partner Andrew Nussbaum heading the team for Wachtell.

Although A&O is a regular adviser to GE in the UK, the latest mandate represents a coup for the City giant's New York arm.

The deal is understood to be the third significant transaction out of the New York office for GE in the last 12 months, after a sustained period of courting the multi-national giant.

Regular advisers to GE in the US include American heavyweights Shearman & Sterling and Weil Gotshal & Manges. A&O's New York office is home to some 110 lawyers, about a quarter of whom are in the corporate group.