The fashion empire founded by Dame Natalie Massenet has been sold to a German rival, bringing an end to years of uncertainty over the future of Yoox Net-a-Porter.

The online luxury seller, which was formed from a merger between Dame Natalie’s Net-a-Porter and Italian brand Yoox in 2015, is to be taken over by Germany’s Mytheresa.

Swiss luxury giant Richemont, which is the current owner of Yoox Net-a-Porter, said it will not receive any cash from the deal but instead secure a 33pc stake in Mytheresa.

Johann Rupert, the Richemont chairman, said he was “pleased to have found such a good home for YNAP”.

The deal follows years of doubt over the business, which had once been seen as a pioneer for luxury online retail but in recent years has struggled with a drop-off in demand.

Before the tie-up with Yoox, Dame Natalie’s Net-a-Porter reportedly attracted interest from bidders including Amazon, as online tech giants sought to move into the premium fashion market. After the company’s merger with Yoox, Dame Natalie stepped back from the business.

High levels of optimism led to Federico Marchetti, who was chairman of YNAP until 2021, claiming that the business was poised to become a “Ferrari” in the market.

However, hopes for the online luxury sector have since dampened as shoppers continue to buy luxury products in-store rather than online.

Matchesfashion, another major online retailer, was put into administration by Frasers earlier this year less than three months after Mike Ashley’s group bought the company.

Frasers said it was not willing to fund a turnaround as Matchesfashion had “consistently missed its business plan targets”.

Richemont, meanwhile, has been under pressure from its shareholders to offload the YNAP business, which has cost the luxury giant billions of euros in writedowns.

YNAP has been racking up consistent losses in recent years, with Richemont warning investors on Monday that it would be writing off a further €1.3bn on the business.

Richemont had been planning to sell the company to another online seller, Farfetch. However, the deal fell through after the British luxury fashion site was bought in a pre-pack administration deal by Coupang late last year.

Piral Dadhania, an analyst at RBC Capital Markets, said the deal with Mytheresa meant that Richemont had the opportunity to “retain some exposure to online multi-brand luxury retail without operational control”.