British café and casual dining company Patisserie Holdings said it had found "significant, and potentially fraudulent accounting irregularities" and suspended its chief financial officer, Chris Marsh.
The owner of the Patisserie Valerie chain said this had significantly impacted its cash position and may lead to a material change in its overall financial position.
Its shares would remain suspended as it investigates its financial position, it added.
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"We are all deeply concerned about this news and the potential impact on the business," Chairman Luke Johnson said.
Marsh has been instrumental in the company's growth since he was appointed to the role in 2006. Under his watch, Patisserie grew from just eight stores 12 years ago to over 200 today.
The company sells cakes, pastries, snacks, meals and drinks under brands including Patisserie Valerie, Philpotts, Baker & Spice and Flour Power City.
Peel Hunt analysts put the company's stock and forecasts 'under review' from a "Buy" rating earlier.
Patisserie Holdings listed on AIM in 2014 and has a market capital of nearly £445 million, according to Refinitiv Eikon data.