Deutsche Bank signalled on Wednesday it could be interested in buying Deutsche Postbank, Germany's biggest retail bank.
"I will rule out absolutely nothing," Deutsche Bank Chief Executive Josef Ackermann told reporters, when asked whether Deutsche might be interested in buying Postbank.
Mail and logistics group Deutsche Post, which controls Postbank, has said it is currently not for sale but that it may make a decision on Postbank's future once the country's domestic mail market is deregulated next year.
Postbank shares rose as much as 3 percent and were up 2 percent at 55.85 euros, bucking a 2 percent fall among European banking shares.
Analysts see Postbank, with its nearly 15 million customers, as one of the country's most attractive targets. The blue chip DAX-listed bank has a market capitalization of around 9 billion euros.
Germany's second-biggest bank Commerzbank said earlier this year it would be interested in Postbank if it were for sale.
Ackermann also said the extent of the current credit market turmoil remained uncertain but it was unlikely there would be a strong lasting burden on the German economy.