A German newspaper and other media on Sunday said a leak of data from Credit Suisse, Switzerland's second-biggest bank, reveals details of the accounts of more than 30,000 clients — some of them unsavory — and points to possible failures of due diligence in checks on many customers. Credit Suisse said in a statement that it "strongly rejects the allegations and insinuations about the bank's purported business practices." The German daily Sueddeutsche Zeitung said it received the data anonymously through a secure digital mailbox over a year ago. It said it's unclear whether the source was an individual or a group, and the newspaper didn't make any payment or promises. The newspaper said it evaluated the data, which ranged from the 1940s until well into the last decade, along with the Organized Crime and Corruption Reporting Project and dozens of media partners including The New York Times and The Guardian. It said the data points to the bank having accepted "corrupt autocrats, suspected war criminals and human traffickers, drug dealers and other criminals" as customers. Credit Suisse said the allegations are "predominantly historical" and that "the accounts of these matters are based on partial, inaccurate, or selective information taken out of context, resulting in tendentious interpretations of the bank's business conduct." The bank said it had reviewed a large number of accounts potentially associated with the allegations, and about 90% of them "are today closed or were in the process of closure prior to receipt of the press inquiries, of which over 60% were closed before 2015." As for accounts that remain active, the bank said it is "comfortable that appropriate due diligence, reviews and other control related steps were taken in line with our current framework." The bank also said the law prevents it from commenting on "potential client relationships." Switzerland has sought in recent years to shed its image as a haven for tax evasion, money laundering and the embezzlement of government funds, practices carried out through the misuse of its banking secrecy policies. But those laws still draw criticism. The Sueddeutsche Zeitung published an excerpt from a statement by the source of the leak. "I believe that Swiss banking secrecy laws are immoral," it said. "The pretext of protecting financial privacy is merely a fig leaf covering the shameful role of Swiss banks as collaborators of tax evaders."