Shares in German payments firm Wirecard fell Wednesday on revelations that a 2017 audit of its troubled Singapore unit could not be completed, but the firm denied a media report blaming accounting “irregularities”.

Hitting back at Tuesday’s allegations by the German financial daily Handelsblatt, Wirecard said auditors from Ernst and Young (EY) could not finalise their local report because they could not access all the necessary documents.

This was due to “restrictions” imposed by Singapore authorities who are investigating the unit’s accounting practices.

“And not as mistakenly suggested in the article by irregularities,” Wirecard said.

Shares in the company shed 5.2 percent to 114.95 euros by 10:20 am (0920 GMT), making it the biggest loser in a DAX index down 0.97 percent.

In its statement, Wirecard stressed that EY had no trouble concluding its audits for the group as a whole in the financial years 2017 and 2018.

The company’s shares have been on a rollercoaster ride this year after a string of Financial Times articles accused it of cooking the books, which Wirecard has consistently rejected.

Many of the fraud allegations have focussed on its Singapore office.

Before the controversy, Wirecard was long seen as a rising star of the “fintech” companies that are upending the traditional world of banking and payments.

Massive growth in the electronic payments it guarantees in exchange for a commission has helped Wirecard, which was founded in 1999, shoot into the blue-chip DAX 30 index.

© Agence France-Presse