Siemens's review of corruption allegations has identified more than €1.5 billion in suspicious payments dating back 10 to 12 years, sources said today.
US law firm Debevoise & Plimpton, which is investigating for Siemens, has told the company internally about the payments, the sources said.
The sum is higher than the amount the German industrial conglomerate had disclosed in December, when it said it had found €420 million in questionable transactions from 2000 to 2006.
The sources said the funds were primarily transfers and cash payments without receipts showing what the payments were for, but that these were not necessarily bribes paid to win business.
In addition, the statute of limitations meant transactions made before 2000 were of little importance in terms of the criminal and tax codes in the United States and Germany , they added.
Siemens declined to comment. Its shares rose 0.8 per cent to €95.22 earlier this morning, slightly ahead of the German DAX blue-chip index.
Munich prosecutors are investigating several former Siemens managers on suspicion of bribery and breach of trust in connection with the allegations, which prompted the departure of its chairman and chief executive. Neither has been implicated.
The US Securities and Exchange Commission is also investigating the allegations.