Earnings for the top equity partners at Richards Butler's Hong Kong base are believed to have dipped from £3m to £1.25m over the past three years.
The office operates as a separate partnership for tax reasons and has 28 partners, with office senior partner Chris Howse and corporate heavyweights David Morrison and David Norman among the highest earners.
A growing equity partnership has meant that profit is distributed more widely. Fourteen Hong Kong partners are now equity partners, whereas it was just a handful three years ago.
The Hong Kong office contributed £27.9m to the firm's £90m revenue last year. The office makes £12.5m profit, which yields an average profit per equity partner (PEP) of around £900,000.
The office is still the most profitable of all of Richards Butler's branches, and this year helped raise PEP from £390,000 in London to £500,000 firmwide. The firm's equity spread worldwide runs from £250,000 to £1.25m. Top of equity in London is around £750,000.
Richards Butler's Hong Kong office is particularly strong in commercial litigation, shipping and real estate. However, the future of the office is still unclear following the UK firm's merger with US firm Reed Smith.
Hong Kong senior partner Chris Howse declined to comment on the profitability of the office.