German media report that Deutsche Bank AG has put at least five of its traders on indefinite leave as part of an effort to restore the company's ethical credibility.

Daily Sueddeutsche Zeitung reports that the unnamed employees were involved in a lucrative "tax carousel" trading system for carbon emissions credits.

A tax carousel refers to a scheme where dozens of companies are used by traders to confuse tax authorities and thereby earn money.

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Deutsche Bank declined to comment on the report Thursday, citing ongoing legal proceedings.

Germany's biggest bank had long denied wrongdoing until a German court case this year brought to light questionable business practices at Deutsche Bank.

Co-CEOs Juergen Fitschen and Anshu Jain announced they wouldn't tolerate unethical behavior when they replaced Josef Ackermann earlier this year.