Wirecard, in a statement, called the report "false, inaccurate, misleading and defamatory. This article lacks any substance and is completely meaningless."
The FT alleged in its investigation that a Wirecard executive had used forged and backdated contracts in a string of suspicious transactions that, it said, raised questions about the integrity of the company's accounting practices.
Reuters was not immediately able to independently verify the FT's allegations.
Shares in Wirecard fell by 18.5 percent at 1519 GMT following the FT report.
(Reporting by Douglas Busvine; Editing by Elaine Hardcastle)
