The full extent of the corruption probe at sports car maker Porsche will be learned today following a raid on the company's headquarters yesterday that saw ­documents seized as part of a probe into alleged insider trading.

The investigation centres on former executives including Wendelin ­Wiedeking, who resigned as chief executive last month after failing in a bid to acquire Volkswagen.

Porsche is facing allegations of breaching “information publication requirements” — effectively insider trading — as laid out by the German Stock Corporation Act.

German financial watchdog BaFin is co-ordinating the probe after ­approaching prosecutors at the start of this month with a file detailing what it claimed are “dirty tricks”. Porsche denies the accusations. It said: “The company will cooperate with the ­prosecutors and is fully ­supporting the investigating officers in order to ­contribute to a swift resolution of the matter.”

German media reported today that arrest ­warrants are likely to be issued in the next few days.

Under Wiedeking, Porsche built up a 51% stake in the much larger VW and wanted to take full control.

In October 2008, the sports car manufacturer dramatically announced it had secured 74% of the stock of VW, leading the VW share price to climb to €1,000 (£864).

At one point, this made VW the most valuable company on the planet.

Since then, VW's share price has dropped more than 40% to €144.

Thousands of speculators got badly burned as the coup fizzled out. The two firms now plan to merge.