Hunton & Williams is understood to be the mystery US firm in late-stage merger talks with CMS Cameron McKenna Nabarro Olswang.
The Lawyer revealed last week that the trio had secured a US merger partner prior to voting through the three-way merger in the UK.
It is understood CMS brought Virginia-headquartered Hunton on board on the basis it would rapidly bulk up in the UK and Europe.
A source said it was “inconceivable” CMS would have opted to merge with Olswang and Nabarro had it not been a precursor to a subsequent tie-up in the US.
If CMS successfully pulls off its mergers with Nabarro, Olswang, and Hunton it would create a £1.35bn firm with a 296-partner broad US presence. Hunton ranked 76th in The Lawyer’s Global 200 2016 report.
The go-live date for the UK combination is May 2017. No details have yet been confirmed regarding the US merger timeline.
CMS has long been the market for a US merger. Sources close to the US firm said that the deal has yet to be finalised but described the talks as being in “advanced stages”.
One of the details understood to be holding back the deal involves the name of the new firm. Sources close to the discussions said Hunton wants to keep its own name without the addition of CMS.
CMS’s various offices operate as an EEIG across Europe, but all partnerships incorporate the CMS brand into each of its office names. In Germany the firm operates as CMS Hasche Sigle.
The German partners are believed to be in favour of the US tie-up due to the number of industrial clients Hunton has in the southern US states, including BMW and Mercedes.
CMS executive partner for global development Duncan Weston declined to comment on the talks.
Hunton managing partner Wally Martinez was not available for comment.
Hunton & Williams has been in the market for a UK merger partner for a while and was previously in discussions with Addleshaw Goddard. It subsequently emerged that Addleshaws had entered into merger talks with CMS but the discussions collapsed at the start of the year.