BERLIN (Bloomberg) - Deutsche Post AG CEO Klaus Zumwinkel will quit after 18 years in charge of Europe's biggest postal service as prosecutors investigate him for tax evasion.

German authorities said yesterday they are probing Mr. Zumwinkel, 64, for possibly evading one million euros ($1.5 million) in taxes by transferring money to Liechtenstein. The company, based in Bonn, did not name a successor. Mr. Zumwinkel's attorney Hanns Feigen declined to comment.

Mr. Zumwinkel's departure came after an investigation by prosecutors in Cologne, Dusseldorf and Bochum that may spread to "several hundred" people. The case follows the resignation of Klaus Kleinfeld at Siemens AG because of a bribery scandal and the trial of labor leaders at Volkswagen AG over improper use of expenses.

"Apparently foundations in Liechtenstein were established for the sole purpose of evading taxes," Eduard Gueroff, a spokesman for the Bochum prosecutor's office, said in a statement on Friday. "The evidence we have so far is very strong."

"The government today accepted the offer by Mr. Zumwinkel to resign," German Chancellor Angela Merkel told reporters in Berlin. "I believe this step was inevitable, after what happened. This was more than I could have imagined, and more than many people could have imagined."

Deutsche Post shares rose as much as 69 cents, or 3.1 percent, to 22.94 euros and closed up at 22.50 euros in Frankfurt electronic trading. The stock has fallen 4.6 percent in 2008, valuing the company at 27 billion euros.

Mr. Zumwinkel's replacement will need to focus on the unprofitable DHL business in the US and decide whether to sell Postbank. The bank today said fourth-quarter profit fell 39 percent to 169 million euros after US sub-prime-related writedowns and because gains from asset sales were not repeated.

"We are bound to see some adjustments to Deutsche Post's strategy," said Axel Funhof, head of transport and logistics analysis at ING Groep NV in Brussels. "After years of loss making, the US business finally needs to be taken care of."

"Mr. Zumwinkel has told the board's executive committee that in the interest of the company, he plans to resign," the company said in an e-mailed statement from Mr. Zumwinkel's attorney.