Weil Gotshal & Manges' Asia managing partner is set to relocate to the US next month, seven years after opening the firm's Hong Kong office.

Japan-born M&A partner Akiko Mikumo is understood to be transferring to Weil's head office in New York where she previously practised.

The firm has declined to comment.

Mikumo's upcoming move from Asia has raised questions about the future of Weil's regional practice.

"[The Hong Kong office] is one that has grown in size, but size isn't always a measure of how things are succeeding," said a partner, who asked not to be named.

"People are speculating: does that signal a reappraisal of the China strategy? And what does that portend for the future of the Hong Kong office in particular? Mainly because of the expense of Hong Kong."

However, in January this year the firm hired Kirkland & Ellis partner Albert Cho to join its private funds group, signalling that the firm is continuing to invest in the region.

The firm did not give any details about its Asia strategy.

Mikumo, who is also a member of the firm's management committee, moved from the US in 2007 to manage the Hong Kong office and lead its planned expansion in Asia. She has overseen the development of Weil's Shanghai and Hong Kong practices, and supervised its 2008 launch in Chinese capital Beijing.

Weil Gotshal opened its first Asian base in Shanghai in 2004, specialising in M&A and private equity. It followed with openings in Hong Kong in 2007 and Beijing in 2008.

At the time of its launch, the firm said it expected the Hong Kong office to provide a platform for expansion into other Asian markets, including India and Japan.

In 2009 and 2010 it boosted the Hong Kong branch with the hire of Henry Ong and John Fadeley from Simmons & Simmons and Clifford Chance respectively.

It later moved from a 5,000sqft space in Gloucester Tower to a 23,000sqft office in Alexandra House in anticipation of further growth.

But in the last 12 months, it has subleased 11,500sqft of the new office, becoming one of a string of US firms making similar moves in the city amid soaring rental rates and last year's drop off in capital markets and M&A work.

According to the firm's website, it currently counts nine partners across the region including Mikumo, with six in Hong Kong, three in Shanghai and one in Beijing.

In Shanghai, there seven lawyers in total, which is understood to be down from a peak of approximately 20 in 2007-2008, sources say.

Related: Is Weil's partner exodus a sign trouble is brewing at the firm's London office?