Fresh investigations into Credit Suisse's World War II-era accounts have uncovered extensive new evidence of Nazi-linked customers that the bank failed to disclose during previous probes, according to documents reviewed by US Senate investigators.

Independent ombudsman Neil Barofsky, reinstated to lead the investigation following UBS's emergency rescue of Credit Suisse, discovered a cache of client files stamped "American blacklist" - a designation for those financing or trading with Nazis or Axis partners.

"The investigation has identified scores of individuals and legal entities connected to Nazi atrocities whose relationships with Credit Suisse had either been previously unidentified, or for which the relationship had been partially identified but the full nature of the bank's involvement has not yet been reported publicly," Barofsky wrote in a December 2024 letter to the US Senate.

Following its acquisition of Credit Suisse, UBS has made the investigation a priority, providing Barofsky and his team with full access to Credit Suisse's private archives. The bank has assigned more than 50 people to support the probe, including forensic accountants, historians, and subject matter experts.

The investigation team discovered approximately 3,600 boxes from Credit Suisse's "Inf department" containing client information, including those who were on the U.S. wartime blacklist for furthering the Nazi cause.

"Credit Suisse hid additional evidence of Nazi ties for years, and even tried to conceal information from our congressional investigation," said senator Chuck Grassley, republican of Iowa.

Evidence suggests the bank deliberately withheld crucial information during the 1990s investigations. Internal comments by bank executives at the time described one panel's draft report as "rather sanitised," but suggested it was best left unchanged.

The investigators discovered several Nazi-linked accounts identified by the bank in the 1990s but never disclosed to investigators, including an operational account controlled by high-ranking Nazi SS officers and a Swiss intermediary allegedly used to move and store looted assets.

"UBS is committed to contributing to a fulsome accounting of Nazi-linked legacy accounts previously held at predecessor banks of Credit Suisse," a bank spokesperson said.

The investigation team is examining records spanning over 300,000 metres of archival shelving, with research ongoing in Zurich, Switzerland, as well as additional locations throughout Europe, South America, and the United States. Barofsky's final report is expected by early 2026.

Prior investigations in the 1990s led Credit Suisse and UBS to pay $1.25 billion in restitution to Holocaust victims, though these new findings suggest the full extent of Swiss banks' Nazi ties remained concealed.

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