Shares in Patisserie Valerie have been suspended after the cafe chain discovered “significant, potentially fraudulent, accounting irregularities”.
The company said these could cause a “potential material” mis-statement in its accounts.
Entrepreneur Luke Johnson owns a 37% stake in the businesses, which also includes Druckers, Philpotts, Baker & Spice and the Flour Power City Bakery.
Finance Director Chris Mash has been suspended, the company said.
Mr Johnson said: “We are all deeply concerned about this news and the potential impact on the business. We are determined to understand the full details of what has happened and will communicate these to investors and stakeholders as soon as possible.”
The company, which was listed on the stock market in 2014, said that the board of directors had been notified of the potential irregularities on Tuesday.
It said it had asked for its shares to be suspended while a full investigation was conducted.
The company’s cash position could be affected and “this may lead to a material change in its overall financial position”, it added.
The last trading update was in May, when Patisserie Valerie said its half-year profits were 14.2% higher at £11.1m
The first Patisserie Valerie store was opened in the Soho district of London in 1926 by a Belgian woman, Madame Valerie. It now has more than 150 stores around the UK and also trades in the supermarket chain Sainsbury’s.
Earlier this year, it was linked with a possible bid for artisan bread chain Gails, owned by Bread Holdings in which Mr Johnson has a majority stake.
Patisserie Valerie – which is known as CAKE on the stock market – was floated at 170p a share and was trading at 429p before its shares were suspended.