Bingham McCutchen's longstanding chairman Jay Zimmerman is to hand the running of the firm to managing partner Steve Browne after 20 years at the helm.

Browne (pictured), who splits his time between the firm's Boston, Silicon Valley and New York offices, will take over leadership responsibilities from 1 June.

Zimmerman will remain as chairman of the Boston-headquartered firm until 2015 and continue to work on firm strategy up to that date. Bingham said Zimmerman's term as chairman had been due to end this September but has now been extended.

The changing of the guard follows a 12.6% fall in revenue to $762m (£458m) last year, Bingham's worst financial performance in six years. The financial results, which the firm announced in February, came in the wake of a decline in US restructuring and securities litigation work.

In a statement, Bingham emphasised that it started succession planning "more than three years ago", and that Browne's installation as managing partner last October was a pre-cursor to Zimmerman stepping down.

The managing partner also took part in a partner leadership programme at the firm, "designed to cultivate next-generation leaders".

Browne also appointed three partners to work with him in his management team: transactional finance co-chair Daniel Papermaster, who assumes the role of operating partner; New York office head Anthony Carbone, who will step into the role of finance partner; and labour and employment practice group leader Debra Fischer, who becomes administrative partner.

In addition to their new management responsibilities, all four lawyers will continue to work with clients.

During his time at the firm, Zimmerman has helped grow Bingham from a 175-lawyer US outfit into an 850-lawyer firm with offices in Europe and Asia.

"It's been an incredibly rewarding run," he said. "The partnership is fortunate to be able to count on Steve and a new generation of leaders to guide Bingham to the next level."