(Bloomberg) -- Swiss prosecutors are investigating a data leak involving thousands of former Credit Suisse Group AG clients who’d reportedly held $100 billion with the bank, in a case set to further discourage whistleblowing in the secretive country.

The Attorney General’s Office confirmed it’s investigating suspected acts of corporate espionage, breach of trade secrets and violations of banking secrecy laws after the information on 18,000 accounts was leaked to an international consortium of media, the OCCRP. The journalists went on to publish a series of exposes last February under the tagline “Suisse Secrets” which reported that the client roster included drug barons and kleptocrats. 

The probe needed sign off from the federal government because the espionage allegations are considered a “political infraction,” the AG’s office said. The bank declined to comment.

Bern’s blessing for the investigation highlights the lengths Switzerland goes to in order to protect banking secrecy, a principle enshrined in Swiss criminal law. The probe is also likely to intensify international criticism of Switzerland’s tendency to prosecute the whistleblower rather than the criminal activity exposed in the leak. 

“This decision is disappointing but not surprising,” Drew Sullivan, the OCCRP Publisher, said. “Switzerland has aggressively defended its bank secrecy to the benefit of organized crime and corruption. Clearly whistleblowers have benefited the public more.” 

Read more: Swiss Bank Secrecy Law Has ‘Chilling Effect,’ Says UN Expert

An anonymous whistleblower gave the information to German newspaper Sueddeutsche Zeitung, which shared the data with a nonprofit journalism group and dozens of other news organizations worldwide. But Tamedia, publisher of the respected Swiss-German daily Tages-Anzeiger which has worked on such collaborative projects in the past, said it couldn’t work on Suisse Secrets because of a risk of falling afoul of the bank secrecy law. 

Oliver Zihlmann, the head of Tamedia’s Research Desk and a member of the International Committe of Investigative Journalists, says this risks being a PR disaster for Switzerland especially if media figures themselves are singled out for prosecution.

“Imagine journalists from international media get summonses in the course of the proceedings because they dared to report that CS catered to oligarchs,” Zihlmann wrote in the paper on Friday. “That would be a disaster for Switzerland’s image.” 

Few Protections

Corporate espionage and banking secrecy are frequently invoked in white-collar prosecutions in the Alpine nation, where whistleblowers have few protections and are typically obliged to first go to their employees with their complain tor risk legal problems. 

Swiss prosecutors have repeatedly gone after local bank employees such as informants Herve Falciani and Rudolf Elmer for breaking secrecy laws despite their revelations leading to major tax investigations in France and Germany.

When the leaks were published a year ago, Credit Suisse issued a statement saying that approximately 90% of the reviewed accounts were closed or were in the process of being closed. 

The reports “appear to be a concerted effort to discredit not only the bank but the Swiss financial marketplace as a whole, which has undergone significant changes over the last several years,” the bank said.

--With assistance from Myriam Balezou.

(Updates with comment from OCCRP in fifth paragraph)

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