City firm SJ Berwin and US firm Proskauer Rose have decided against a merger, the firms announced today in a statement.

‘At this stage in our discussions, we recognised that the timetable necessary to reach the agreements that would ensure the successful integration of our firms is not workable at this time,’ the statement said. ‘Accordingly, and with considerable regret, we have mutually determined to halt our talks.’

The firms had been discussing a tie-up for around nine months. Had they gone ahead, it would have marked the fourth major transatlantic merger of the last 12 months, and created a firm with more than £600m in combined revenues.

The statement continued: ‘Our discussions began on the basis of a longstanding and profound mutual respect founded on outstanding lawyering ability, a commitment to client service and synergistic practice capabilities. Our discussions end with the same profound respect, and with the greatest admiration for all the partners we have met during the course of this process.’

SJ Berwin also today announced half-year revenues of £87m in the six months to 31 October, up by 9% on the same period last year. Profits rose by 34% in the same period.

Managing partner Rob Day said: ‘This is a strong performance which marks a significant step in our financial recovery. We expect to maintain growth in revenue and profit in the second half of this financial year. Recent matters on which we have advised demonstrate rising activity and market share in our core areas such as corporate, finance and real estate.

‘Work pipelines in M&A, private equity and investment funds are at their strongest for over 12 months. Counter-cyclical practice groups such as litigation, restructuring and intellectual property are very busy and growing to cope with demand.’

Earlier this week, national firm Hammonds and US firm Squire Sanders & Dempsey announced that partners had voted through a merger, creating a 1,275-lawyer transatlantic practice with $625m (£387m) in combined revenues. In May, City firm Lovells and US firm Hogan & Hartson merged to created Hogan Lovells. City firm Denton Wilde Sapte and US firm Sonnenschein Nath & Rosenthal merged in September to create SNR Denton