Infineon Technologies, the world's third largest DRam memory maker, is under increasing pressure to say why its chief executive, Ulrich Schumacher, resigned without explanation last week.

Infineon executives have so far refused to talk about a special board meeting at which Schumacher reportedly resigned "for personal reasons".

The outspoken Schumacher has been responsible for leading Infineon since it was spun off from parent Siemens in 1999, getting it through its initial public offering and helping it to profitability for the first time in two years.

Peter Fischl, Infineon's chief financial officer, said: "There is no change in strategic direction and policy."

He also claimed that there are no concerns with accounting, the balance sheet, or current performance. But he did confirm that plans to relocate Infineon from Germany have been shelved.

Schumacher was one of the most outspoken chief executives in the DRam industry, hitting out at high German taxes and threatening to move the company's HQ to Switzerland.

He was also responsible for increased outsourcing to China and Taiwan, in a bid to remain competitive.

"This is a bit shocking," said Andrew Norwood, senior memory analyst at Gartner Dataquest.

"One of Infineon's slogans is 'Never stop thinking' but you have to ask if that's what the board just did.

"Schumacher turned that company around and it's a real shame that this is how it ends. He may have been a bit pushy and abrasive but the board needs to look at the big picture.

"He was looking to outsource jobs and reduce taxation - all the things a good chief executive does. Maybe his outsourcing comments were a step too far. He may have just been moving too fast for a conservative German business."

Following Schumacher's departure, two other employees have left. Christoph Sieder, head of communications, and Matthias Poth, head of the corporate centre, resigned last week with immediate effect.