Watches of Switzerland shares fell almost 30% on Friday, on course for the biggest one-day drop on record, as Rolex's purchase of retailer Bucherer raised questions about Watches' prospects.

Rolex announced on Thursday that it would buy luxury watch retailer Bucherer for an undisclosed amount, adding the watch retailer will operate independently.

Watches of Switzerland, which sells Rolex, Piguet and Cartier watches, said in a statement on Friday that Rolex confirmed that there will be no change in the Rolex processes of product allocation or distribution.

"There will be no operational involvement by Rolex in the Bucherer business," Watches of Switzerland Group said in a statement.

Watches of Switzerland shares hit their lowest level since December 2020 and were last down 26%.

"Inevitably the market is debating today the extent to which the news signals a growing risk of a weakening future relevance of WOSG to a key supplier for the group," Jefferies analysts said in a note.

Bucherer owns more than 100 sales outlets worldwide, of which 53 distribute the Rolex brand and 48 distribute the Tudor brand. (Reporting by Joice Alves; editing by Dhara Ranasinghe)