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 - designed to withstand 100 mph winds - 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.

Daniel Timbers, 29, and Barry Joy, 56, were working at Harford Attachments in Spar Road when they were killed, shortly after 09:00 BST on Monday.
The men are believed to have been working in a paint-spraying area.
Their bodies were removed from the site on Tuesday afternoon.
A forensic search has been carried out at the company, which makes buckets for diggers.
Det Ch Insp Paul Durham said "significant progress" had been made with forensic inquiries and obtaining witness statements.
"Evidence gathered so far suggests there has been a flashover explosion, which occurs when you have a build-up of toxic fumes," he said.
"This, combined with some sort of ignition, has caused a fire-ball effect."
The Health and Safety Executive said its inspectors and electrical safety experts would be gathering evidence.

Emergency services found a Mini had crashed head-on with a Volvo in Buxton Road, Hazel Grove, at about 16:00 BST on Sunday, police said.
Philip Clayton, 43, died at the scene. A 23-year-old man is in a serious condition in hospital.
Buxton Road was closed while investigations took place. Police are appealing for witnesses to contact them.
A man and a woman were also taken to hospital with serious but not life-threatening injuries.
Aquascutum, whose luxury raincoats have been worn by royalty and film stars, is being sold for $120m (£97m).
[NEXT_CONCEPT]
Two men killed in an explosion at a factory in Norwich died from the "effects of fire and inhalation of fumes of combustion", post-mortem examinations have found.
[NEXT_CONCEPT]
A man has died in a head-on crash in Greater Manchester.