King & Wood Mallesons (KWM) has held discussions with US firm Morgan Lewis & Bockius about a global tie-up, it has emerged.

It is understood that talks with Morgan Lewis have taken place during the past few months, with the US firm's chair Jami Wintz McKeon involved for her firm, opposite KWM global managing partner Stuart Fuller.

One option on the table was a multi-profit centre union, using a Swiss verein structure.

However, is thought that the resignation of high profile City funds partner Michael Halford from KWM may have caused discussions to cool, and it is unclear whether they are still continuing in any form.

KWM has long sought a deal in the US to complete its global footprint, though given the difficulties in finding a suitable partner it had previously switched its focus to a best friends approach.

Were a union to happen, the merged firm would have offices across the US, Europe, Asia and Australia. KWM posted flat global revenue of $1.02bn (£714m) for 2015, while Morgan Lewis posted revenue of $1.844bn.

News of the talks comes as KWM's new European management team has flown to Asia to speak to the firm's Chinese leadership about finding a way forward for its European arm, which is under pressure following a series of high profile partner exits.

Europe, UK and Middle East (EUME) managing partner Tim Bednall and senior partner Michael Cziesla – who were voted into their new roles last month – are understood to be in China to discuss options for the European partnership, which could include the Chinese partnership providing some form of financial assistance to the legacy SJ Berwin business.

Halford resigned from the firm last week with three other London partners, leading to KWM halting a planned recapitalisation. The programme was intended to bolster the EUME business – which has debts of £35m – by bringing in more than £14m via a partner capital call. An assessment of the financial impact of the recent resignations is expected to be completed in around three weeks' time.

Halford was one of four of KWM's highest billing London partners to resign last week, alongside private equity partner Jonathan Pittal, corporate partner Andrew Wingfield and former managing partner Rob Day. The quartet are understood to have been bringing in around £9m in annual billings.

Departures from the firm are continuing, with news emerging today (4 November) that Squire Patton Boggs has hired London energy partner Neil Upton alongside a team of four lawyers, while earlier this week it was announced that a five-lawyer Germany team – including Germany banking and finance head Sabine Schomaker – is leaving to join Taylor Wessing in Frankfurt.

Morgan Lewis is no stranger to circling firms in financial difficulty. In late 2014, the US firm absorbed the bulk of now-defunct Bingham McCutchen, while it has also hired large groups of lawyers from defunct firms such as California's Brobeck Phleger & Harrison, Dewey & LeBoeuf, Howrey and Thelen.

KWM and Morgan Lewis declined to comment.