Investigators are probing the entire four-person board of German electronic payments firm Wirecard on suspicion of market manipulation, Munich prosecutors told AFP Friday, after the company repeatedly put off publication of its 2019 results.

"Suspicions are based on the fact that managers at Wirecard could have given misleading signals for the company's stock market price in ad-hoc releases", the prosecutors said, adding that they had been searching the company's headquarters outside Munich since early Friday morning.

Following a series of articles in the Financial Times last year alleging accounting irregularities, KPMG was called in by Wirecard's supervisory board to audit its books for 2016-18.

Wirecard has attempted to present intermediate steps of the audit in a favourable light, including in the March 12 and April 22 statements now under prosecutors' microscope.

But that did not get its share price off the rollercoaster, falling as low as 77 euros ($87) at one point and closing this week down 10.8 percent since January, at 95.88 euros.

KPMG's final report, released at the end of April, said that vital documents were missing relating to transactions carried out by third parties on Wirecard's behalf.

Nor were the auditors able to determine whether some transactions corresponded to real sales.

Clouds are gathering over Wirecard
Clouds are gathering over Wirecard AFP / Christof STACHE

The transactions concerned, passing through escrow accounts and amounting to around one billion euros, could not be verified as originating from Wirecard clients.

The company had become a darling of the German financial world after taking traditional banking heavyweight Commerzbank's place on the DAX blue-chip index in 2018.

German financial markets watchdog BaFin originally stepped in to investigate possible collusion between so-called "short sellers" betting against Wirecard shares and the Financial Times.

But the supervisor has now itself filed charges against the payments processor's board.

"Today the company's premises were searched," Wirecard confirmed in a statement, adding that "the investigations are not targeting the company, but members of its management board."

"The company is fully cooperating with the investigating authorities."

So far, founder and chief executive Markus Braun has resisted calls for his departure from angry shareholders, although his jurisdiction was restrained by a recent reorganisation decided by the supervisory board.