Siemens Energy shocked markets in late June when it announced several problems at Siemens Gamesa, one of the world's biggest wind turbine makers, just weeks after it fully acquired the business it had only partly owned.
Earlier this month, the company announced 2.2 billion euros in charges, including 1.6 billion euros to fix the onshore wind problems - short of analysts' worst-case estimates but still casting doubt over whether it would keep the business.
According to Wednesday's report, a special committee made up of CEO Christian Bruch and members of the board had conducted simulations showing the cost of the onshore problems could be almost three times as high as the amount set aside.
Shares in Siemens Energy briefly dropped in response to the report.
A spokesperson at Siemens Energy referred to the company's Aug. 7 statement saying the cost of the onshore problems would amount to 1.6 billion euros.
($1 = 0.9236 euro)
(Writing by Friederike Heine, Editing by Jonathan Oatis and Mark Potter)
