SJ Berwin is reported to be in the very early stages of merger discussions with Mayer Brown. So that will make it SJ Berwin's third crack at a US merger.

Discussions are currently restricted to the grands fromages of both firms, according to a Lawyer report, but if the merger does go ahead it could result in something of a transatlantic behemoth. With SJB pulling in £179m in 2010/11 and Mayer Brown $1.07bn (£706m), the union would create a £900m powerhouse and propel the newly minted firm up alongside the likes of Hogan Lovells. And whilst the pair's revenues might be worlds apart, partner profits are pretty similar - £630k at SJB and $1.07m (£682k) at Mayber Brown - which bodes well for a merger.

For SJB the motivations are clear: the firm would get the US boost it's long been seeking and a merger would give the private equity focussed firm the extra muscle to compete for the biggest international deals. For Mayer Brown (voted Golden Turd in the 2011 Firm of the Year survey, even though the firm took the "Most Improved" award in 2012) a European merger may help its international practice and also its London office, which has been hit by partner defections of late.

Useful bedtime reading for SJ Berwin partners

But before anyone gets too carried away, SJB has a history of broken relationships with US firms. Two years ago, the firm tried to woo San Francisco-based Orrick, but was left heartbroken after the US firm pulled out. SJB then jumped straight into talks with Proskauer Rose, calling it a day after nine months and at the cost of several SJB partners who, narked by the never ending discussions, defected.  

SJB declined to comment and a spokeswoman for Mayer Brown said "we do not comment on market rumour and speculation". Draw your own conclusions, alleged-fact fans.