Deutsche Bank AG said seven employees who trade emissions allowances are suspects in a tax-evasion probe.

Deutsche Bank assumes the allegations by prosecutors against its employees can be rebutted, spokesman Christoph Blumenthal said by telephone. "In any case the presumption of innocence applies."

Prosecutors and tax investigators on Wednesday searched Deutsche Bank, HVB Group and RWE AG in a raid on 230 offices and homes to investigate $238 million of suspected tax evasion. The probe targeted 150 suspects at 50 companies. Three suspects were arrested; none works at Deutsche Bank, Guenter Wittig, a spokesman for Frankfurt's chief prosecutor, said by phone Thursday.

The raids were the biggest related to a fraud that may have tainted an estimated 7% of European Union carbon trades in 2009. The U.K., France and the Netherlands have also said they are investigating "carousel fraud," in which traders buy and sell carbon permits, collect tax and disappear before turning it in to authorities.

Frankfurt-based Deutsche Bank has control and compliance mechanisms to ensure that all emissions trading and transactions are done in compliance with applicable law and regulation, Blumenthal said.

Munich-based HVB, the German unit of Italy's UniCredit SpA, said Thursday that prosecutors asked for help in connection with a probe of clients, not the bank.

RWE's supply and trading offices were searched, spokesman Michael Rosen said. RWE said it is cooperating but "hasn't been charged and is not under suspicion."

Tax investigators seized documents and e-mails at the Bavarian Stock Exchange in Munich Wednesday, Managing Director Andreas Schmidt said in an interview Thursday. Investigators were probing two of the 28 companies registered for the trading of emission certificates on the exchange's Greenmarket platform, he said.

The Munich exchange suspended the two companies from trading, he said, but declined to identify them because the investigation is pending and they traded "only very marginally" in March.

The Munich companies Nexis Solar Technologies GmbH and Roter Stern GmbH were suspended from Greenmarket Wednesday, according to a note in the exchange's gazette.

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