The black hole in the accounts of the troubled cafe chain Patisserie Valerie was as much as £94m, more than twice previous estimates, according to forensic accountants.

The company plunged into administration in January after it was unable to secure new bank finance following the discovery of “potentially fraudulent” accounting irregularities.

The progress report by its administrators, KPMG, published on Friday, said analysis by a team of forensic accountants had concluded the accounts had been overstated by approximately £94m.

Previous estimates had put the figure at £40m, but a breakdown of the new sum suggests Patisserie Valerie’s cash position had been overstated by £54m. The company’s debts had also been understated and the amount it was owed overstated, to a combined value of £17m. There was also a £23m discrepancy in the way it had valued its assets.

The collapse of Patisserie Valerie, which employed 3,000 people and was chaired by Luke Johnson, a serial investor, was one of the biggest stock market upsets of recent years. The company was valued at £450m before it flagged up the potential fraud, and the administration wiped out shareholders, including Johnson, who had a 37% stake.

KPMG expects to raise about £17m – last month it sold the Baker & Spice cafe business for £2.5m – by dismantling the parent group’s seven companies that are currently in administration. It is not clear how much money creditors will recoup.

Some of the companies, such as Philpotts, will pay out healthy dividends, but for others, such as the plc, there will be zero. Johnson is one of the biggest financial losers from the collapse, as he made a £10m unsecured loan to Patisserie Valerie at the height of the crisis and is a creditor of the plc.

Patisserie Valerie’s finance director, Chris Marsh, was arrested and bailed following the accounting scandal, which surfaced in October. The Serious Fraud Office has confirmed it has opened a criminal investigation into an individual but has not commented further.

In addition to the SFO, the case has attracted the attention of a multitude of regulators, with the Financial Reporting Council, the Insolvency Service, the Aim market regulator and the HMRC fraud investigation service also combing through company documents and servers.

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Given the level of interest, KPMG said the company would have to establish whether there were sufficient grounds for legal claims against a number of parties, a group that could include Patisserie Valerie’s auditor, Grant Thornton.

To that end, KPMG is advising creditors to sanction the hiring of a second administrator to review all potential legal claims. This is due to potential conflict of interest, as Grant Thornton is KPMG’s auditor.

About 900 cafe workers lost their jobs when Patisserie Valerie stores and concessions were shut by the administrators in January, before the chain was sold to the Irish private equity firm Causeway Capital Partners.

Patisserie Valerie Holding’s Philpotts sandwich chain was sold to the Spar store operator AF Blakemore & Son. The two deals raised £13m and saved about 2,000 jobs.

The company, which was founded in 1926 by Esther van Gyseghem, who became known as Madame Valerie, expanded rapidly after being bought by Johnson’s Risk Capital in 2006. It floated on the stock exchange in 2014.