Aquascutum, whose luxury raincoats have been worn by royalty and film stars, is being sold for $120m (£97m).
Reports suggest Chinese buyers are acquiring the clothing retailer, which started in London in the 1850s.
Its illustrious fans have included the Queen Mother, Margaret Thatcher and actors such as Cary Grant.
But after the British firm was saved from administration in 2012, it has mainly focused on China and last year saw its UK sales fall 16%.
Hong Kong-based YGM Trading, which bought it for £15m four years ago, said Aquascutum is due to be sold in March 2017 to two buyers.
The unnamed acquirers have made a $5m down payment for exclusive rights to the deal, YGM said in its annual report this week.
Chinese textile firm Shandong Ruyi Group is understood to be one of the buyers, according to Bloomberg.
Aquascutum started as a Mayfair tailors in 1851, rising to prominence after its founder, John Emary, patented the first waterproof textile.
Its trench coats were worn by British soldiers during the First World War, while in 1953 its wyncol fabric was used by explorer Edmund Hillary in the first confirmed ascent of Mount Everest.
The coats were also a regular feature on the silver screen, with Sean Connery wearing one in Another Time, Another Place in 1958 and Sophia Loren in The Key.
However, the retailer has struggled in recent years, closing its Nottinghamshire factory in 2012 and then falling into administration.
Under YGM’s ownership, the company’s primary focus has been China, with 135 of its 146 outlets located in mainland China, Hong Kong, Macau and Taiwan.
Last year it closed 14 stores in China amid declining sales, but opened one in Europe.
In the UK, its three remaining standalone stores are in Westfield London, Great Marlborough Street and Jermyn Street.