Patelco Credit Union

Nearly a half-million members of Patelco Credit Union, with branches across the Bay Area and Northern California, have not had access to banking services following what the CEO called a “serious security incident” over the weekend.

The Dublin, Alameda County-based credit union announced at 7 a.m. and said their services were unavailable, including online banking, mobile app, direct deposits, transfers and debit and credit card transactions.

Patelco members received an email from President and CEO Erin Mendez about the security incident, although the details of the incident were not disclosed.

As of 11:30 a.m. Monday, the Patelco website was still not functioning.

The email said the credit union was working with cybersecurity experts to assess the situation and restore services. Mendez also said an estimated time of restoration was not available.

Patelco is the 27th largest credit union in the country with $9.8 billion in assets and 455,000 members with more than 1 million accounts. The non-profit credit union has 37 branches in the Bay Area and Sacramento area. It is one of the oldest credit unions in the U.S., begun in 1936 for employees of the former Pacific Telephone and Telegraph Company, now known as AT&T.