Antitrust regulators at the European Union (“EU”) have accused Deutsche Bank DB, Credit Agricole CRARY and Credit Suisse CS of being involved in a bond trading cartel for a period of about seven years (2009-2015). One more global bank is said to be under the suspicion.The banks are charged of rigging prices of U.S. dollar-denominated government bonds by exchanging “commercially sensitive information and coordinated on prices” mainly through online chatrooms.Deutsche Bank said that is fully cooperating with the regulator on matters related to the investigation. Further, it expects to pay no amount as penalty. Notably, per the European Commission guidelines, whistleblowers are often immune to paying fines. Thus, Deutsche Bank’s comment suggests that it could have blown the whistle on the cartel.The other two identified banks have also confirmed their co-operation with the EU authorities in the matter.As a matter of fact, the EU can enforce a fine of up to 10% of a bank’s global turnover for violating rules. Per EU rules, the banks can demand to examine the commission’s evidence and put forth explanations. They can also request a hearing on the matter before the regulator takes a final decision. The banks can provide information or seek to agree a settlement in exchange for reduced fines. Further, there is no legal deadline for the EU to complete its investigation.Shares of Deutsche Bank and Credit Suisse breached their 52-week lows yesterday, when the news of the scandal broke. Further, Credit Agricole was down 2.8% at the end of yesterday’s trading session.All the banks mentioned above currently carry a Zacks Rank #4 (Sell).You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.Looking for Stocks with Skyrocketing Upside?Zacks has just released a Special Report on the booming investment opportunities of legal marijuana.Ignited by new referendums and legislation, this industry is expected to blast from an already robust $6.7 billion to $20.2 billion in 2021. Early investors stand to make a killing, but you have to be ready to act and know just where to look.See the pot trades we're targeting>> Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Credit Agricole SA (CRARY): Free Stock Analysis Report Deutsche Bank Aktiengesellschaft (DB): Free Stock Analysis Report Credit Suisse Group (CS): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research