Private Swiss bank Julius Baer Holding AG said client data from its Cayman Islands unit were stolen, a major embarrassment for a bank that prides itself on its discretion and secrecy.

The bank said it suspects a former employee stole old client records and disclosed them to the Swiss media. It doesn't know whether the information has been misused or whether any current clients are affected, said Juerg Staehelin, a spokesman for the Zurich-based bank. The bank isn't aware of misuse of the data aside from the leak, he said.

The leak comes at a bad time for the 115-year-old bank, which is struggling to attract private banking clients in the face of new and intense competition from larger rivals such as UBS AG and Credit Suisse Group AG. Baer also faces the expense of adapting its business practices to Swiss and foreign-government regulations that were adopted in a bid to clamp down on terrorist funding after the Sept. 11, 2001 attacks. The regulations require new measures to monitor clients to detect suspicious financial transactions.

Baer is adopting those measures while also trying to keep the long tradition of Swiss banking, with client confidentiality as a cornerstone of its business.

Identity theft is growing globally. In a recent string of high-profile cases, personal data were stolen from banks, universities and stores in the United States and Europe, among other sources, via online computer security breaches.

The Baer case, however, may be different. So far, it appears it doesn't involve cyber-crime but the age-old crime of a former employee swiping some records, Staehelin said. "It's not due to a hacker or an IT leak. It looks like something caused by a disgruntled former employee who is abusing his position," he said.

The bank said that police in the Cayman Islands and Zurich are looking into the matter. News of the theft was first reported by Cash, a Swiss financial weekly.

The records pertain to clients from 1997 to 2002, the bank said. The data had been held at its Cayman Islands unit, Julius Baer Bank & Trust Co., which offers trust-fund services to international clients, Staehelin said.

Julius Baer Holding traces its origins to Bank Julius Baer, founded in 1890, and has served private clients ever since. After opening its first foreign unit in 1940, the bank now has offices in London, Luxembourg, Milan, Frankfurt, Vienna, Dubai, Grand Cayman, Los Angeles and New York. The small bank caters to ultra-wealthy individual clients.