Bingham Dana is merging with New York firm Richards & O'Neill - a move which will more than double its presence in the city.
Bingham Dana, which also has offices in Hartford, London, Los Angeles, Singapore and Washington DC, is known internationally for its strong finance practice and particularly for its financial restructuring group.
But the New York expansion, which adds 75 lawyers to what is currently a 50 lawyer office, focuses on corporate, real estate and litigation.
The two firms got to know each other after working for separate parties on a major pharmaceutical litigation last year. A client of both firms, financial services group Legg Mason, suggested that the two firms should talk and an agreement has been finalised in just four months.
Bingham Dana managing partner Jay Zimmerman says: "Our view at this point is that while we continue to grow through internal growth and lateral hiring, we did want to achieve critical mass in New York.
"We opened in 1997 with 20 lawyers and we are now up to 50, but we had to get to the next level to create the right platform for further growth."
Clients of Richards & O'Neill include Kawasaki Heavy Industry, Kirin Beer and Fujisawa Healthcare.