The Protection Association of Investors (SdK) wants the Adler subsidiary Adler Real Estate to be examined more closely.
She suspects irregularities in the company's balance sheet.
The request for a special audit is to be submitted to the shareholders of Adler Real Estate for a vote at the Annual General Meeting on August 31.
It was delivered to the company this week.
In particular, the special auditor should clarify what influence Cevdet Caner has on Adler, and also the role of persons and companies close to him.
The Austrian businessman heads one of Adler's largest financiers.
His wife is the second largest Adler shareholder.
The sale of a property in Düsseldorf for 375 million euros to a company owned by Caner's brother-in-law would also be examined.
The financial regulator Bafin believes that the object was overvalued.
Details of a EUR 265 million loan that Adler Real Estate granted at the end of December and the sale of Accentro Real Estate AG to an Azerbaijani investor, which Adler was never fully repaid, would also be of interest.
According to the SdK, the past few weeks have shown that neither the management of Adler Real Estate nor the parent company, the Adler Group, have any interest in transparent clarification.
In order to obtain clarity, a special test is therefore necessary.