Authorities raided Deutsche Bank and private homes Wednesday FRANKFURT, Germany, Dec. 12 (UPI) -- Germany's Deutsche Bank said Wednesday a co-chief executive officer and its chief financial officer were under investigation as part of a tax dodge case. Five people have been arrested out of about 25 involved in the alleged conspiracy to avoid paying a tax on sales of carbon trading certificates, The New York Times reported. The bank executives caught up in the case, co-Chief Executive Officer Jurgen Fitschen and Chief Financial Officer Stefan Krause, were not among those arrested, the Times said. Private homes and bank offices were raided by authorities Wednesday. The raid included 500 officers searching the Deutsche Bank office in Frankfurt, Germany. The carbon trading certificates are part of an incentive program to lower carbon emissions. Companies are assigned a set figure for carbon emissions and, if they can stay under their limit, are awarded their unused portion to sell to other companies that may be close to or over their limits. The program is designed to offer an incentive to companies for staying under their emissions limit. The bank said it was cooperating with the investigation, but also said it had changed its tax reporting process according to updated rules. "Unlike the Public Prosecutor's Office, Deutsche Bank is of the opinion that this correction took place in due time," the bank said in a statement.