City firm Rakisons is in the final stages of merger talks with Washington DC firm Steptoe & Johnson.
Neither firm has voted on the merger - which would give the 300-lawyer Steptoe & Johnson its first significant European presence - but they hope to go live as a merged firm on 1 October.
Steptoe & Johnson is one of the largest firms in Washington and is known for its international trade work - covering trade litigation, advising on import and export matters, and on pure international law such as cross-border disputes.
It is also strong in telecoms and technology, corporate, competition and international litigation and arbitration.
Fourteen-partner Rakisons specialises in telecoms, technology and corporate work.
Steptoe & Johnson rec-orded a turnover of $119m (£74.4m) for the last financial year, with profits per partner at $435,000 (£272,000). Rakisons' profits per partner are understood to be about the same, with a turnover of £7.4m.
Steptoe & Johnson's chairman Lon Bouknight says: "Both our clients and the work are becoming one and the same in the US and Europe.
"We very much like the fit of [Rakisons'] telecoms and technology practices, and their corporate practice with ours."
Steptoe & Johnson has a one-lawyer office in Brussels that does trade and technology regulation work, and plans to expand both that and the London office, sending in lawyers to work there. A combination of the two firm's names will be used in London to begin with.
Its clients in telecoms include Motorola, WorldCom and Spanish company Telefonica. In international trade it acts for Boeing and Mitsubishi Heavy Industry and in corporate it acts for Deutsche Bank.
Rakisons senior partner Tony Wollenberg says: "We have had a large US flavour to the practice virtually our entire existence, and [Steptoe & Johnson] has a client list to die for, strong management, a very strong regulatory and telecoms practice and strong international reach."