Shares in airport services operator Alpha Airports - which is carrying out major work at Birmingham International Airport - were suspended yesterday after auditors withdrew their approval of annual results for the year to January 31.
Alpha said it had requested a temporary suspension of its shares after the move by its auditors, PricewaterhouseCoopers.
The group said the withdrawal of the approval related to "enquiries by the auditors into a series of related transactions connected with a major contract awarded to the company during the financial year".
Alpha is now "urgently" seeking to clarify the position with PricewaterhouseCoopers.
However, PWC's move means publication of Alpha's audited accounts for the year and its annual shareholder meeting, normally held in June, will be delayed. A spokesman for Alpha insisted PWC's action was unrelated to Alpha's January announcement that it may have been the victim of a fraud by a third party, which it has declined to name.
Last month, when Alpha published its full-year results, it said further investigation has indicated the group lost up to #2.5 million in a fraud across several European countries.
Alpha is prosecuting the company itself before handing over information to the police and the Crown Prosecution Service.