The US legal market is preparing for one of the biggest mergers in its history with the news that Dewey Ballantine and Orrick Herrington & Sutcliffe are in merger talks.

New York-based Dewey and San Francisco’s Orrick confirmed this week that they were in talks regarding a merger, which would mark the most significant tie-up in the market since the 2004 union of Wilmer Cutler & Pickering with Boston’s Hale and Dorr. A combination of the top 50 outfits would create a firm with almost 1,500 lawyers and revenues of just under $1bn (£535m).