Shares in Patisserie Valerie have been suspended after the company discovered "significant, potentially fraudulent, accounting irregularities".
It was not immediately clear whether stores would be able to remain open for the time being or what the future would hold for the company's 2,500 staff.
Chairman Luke Johnson said: 'We are all deeply concerned about this news and the potential impact on the business.
In its statement on Thursday, the firm said that over the past 24 hours it had "undertaken further investigation into the financial status of the company".
In a flurry of announcements, the board revealed it has just been made aware of a winding up notice issued by HM Revenue and Customs to its principal trading subsidiary Stonebeach Limited in September.
The first Patisserie Valerie was opened in London's Soho district in 1926 by the Belgian-born Madame Valerie, according to the company's website, expanding later under new owners.
It was floated on the AIM stock market, for smaller companies, in 2014.
"As a outcome, the directors and the company's professional advisers are assessing all options available to the business to keep it trading and will update the market in due course".
Earnings before interest, taxation, depreciation, and amortisation were £13.6m during the period, up 11.6pc year-on-year. "Given our duty of client confidentiality it would be inappropriate for us to comment".
Patisserie Valerie trades from more than 200 stores - including outlets in Wolverhampton, Telford, Shrewsbury and Resorts World in Birmingham - and also has a partnership with Sainsbury's, with branded counters present in the supermarket.
Entrepreneur Johnson bought a 70 per cent stake in the business in 2006, and still holds a 37 per cent interest, having enjoyed success with other chains like Pizza Express.
In 2001 he co-founded Risk Capital Partners, which owns stakes in companies including Majestic Bingo and swimming goods firm Zoggs.
His website also says he is a board member of sporting goods company Zoggs and Brompton Bicycles.
Among the major investors in Patisserie Holdings are Octopus Investments, which owns 8%.