Mayer Brown is to merge with leading Hong Kong firm Johnson Stokes & Master.

The deal, which will complete on 28 January, will dramatically increase the Anglo US firm's presence in Asia, handing it a seven-office network with more than 260 lawyers and a turnover of $160m (£80.5m).

Talks between the two firms began four months ago after Johnson Stokes approached Mayer Brown. Johnson Stokes' 41 equity partners voted through the merger unanimously two days ago (19 December).

Under the terms of the deal, Mayer Brown will practise as Mayer Brown JSM in Asia.

Elaine Lo, chair of Johnson Stokes' partnership board, will head up a new Asia Board as well as joining Mayer Brown's management committee, along with senior litigation partner Nick Hunsworth.

Mayer Brown vice chairman Paul Maher, who led the negotiating team, said the merger meant the firm had already over delivered on its three-year Asia strategy, which kicked off with the opening of a small office in Hong Kong at the start of the year.

"Our strategy was to build an Asian practice over three years to a point where we had 100 lawyers," he said.

"I believe this deal makes us unique in that we will have 1000 lawyers in the US, 500 in Europe and 260 in Asia."

Maher said Johnson Stokes, which operates a lockstep partnership, had been attracted to Mayer Brown because of its transatlantic platform and culture. The partners will be admitted directly into Mayer Brown's equity. Average profits per equity partner at Johnson Stokes are understood to be slightly higher than Mayer Brown's figure of $1.135m (£571,000).

The deal comes just two months after Reed Smith brokered a deal to take on Richards Butler's 28-partner legacy Hong Kong office.

Roger Parker, Reed Smith's Europe and Middle East managing partner, said: "This is further evidence of the consolidation of the international legal market and it will be interesting to see how law firms react, particularly those in London without Asian practices."

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