Guardian Credit Union, a member-owned, not-for-profit credit union headquartered in Oak Creek, Wisconsin, disclosed a data breach that may have exposed sensitive personal and financial information. The credit union, which was founded in 1934, serves over 35,000 members across several southeastern Wisconsin counties and holds more than $225 million in assets.
The types of personal information exposed in the breach included Social Security numbers, drivers license information and financial account information. Because the breach involved both identity documents and financial data, this incident carries a heightened risk of identity theft and financial fraud for those affected.
Guardian Credit Union stated in its notification letter that it was “unable to provide further details about the nature of the event” due to the requirements of Massachusetts law. The credit union directed affected individuals to a dedicated assistance line to obtain additional information about what occurred.
According to the notification letter, the credit union became aware of suspicious activity and launched an investigation with the support of third-party forensic specialists to confirm the security of its network. After completing that investigation, Guardian Credit Union engaged a separate third party to conduct what it described as “a comprehensive and time-consuming review” of the information at risk.
The credit union then performed additional work to verify the affected information and locate mailing addresses for the people it needed to notify. The total number of individuals affected nationwide was not disclosed in the filing.
Guardian Credit Union’s response
The breach was disclosed to the Massachusetts Office of Consumer Affairs and Business Regulation on Aug. 6, 2026, with nine Massachusetts residents identified as affected.
Guardian Credit Union is offering affected individuals 24 months of complimentary credit monitoring and identity protection services through Experian IdentityWorks at no cost. Individuals who received a notification letter can enroll by visiting the Experian IdentityWorks enrollment page and entering the activation code included in their letter.
Enrollment must be completed by the deadline printed in each person’s letter. The terms and conditions for the identity restoration portion of the service are available online.
The membership includes several features, according to the notification letter. These include an Experian credit report at signup, daily credit reports for online members, active monitoring of Experian, Equifax and TransUnion credit files, access to identity restoration specialists and $1 million in identity theft insurance. The identity restoration support continues even after the membership expires through Experian’s ExtendCare program.
If affected individuals believe there was fraudulent use of their information as a result of the incident, they can speak with an Experian agent. If it is determined that identity restoration support is needed, an Experian Identity Restoration agent will work with the individual to investigate and resolve each instance of fraud.
Affected individuals who have questions can call Guardian Credit Union’s dedicated assistance line at 888-616-9569, available Monday through Friday from 9 a.m. to 9 p.m. Eastern Time, excluding U.S. holidays.
They can also reach the credit union by email at privacyevent@guardiancu.org. For questions about the Experian IdentityWorks product or identity restoration services, individuals can contact Experian at 1-877-288-8057 by Dec. 31, 2026.
In its notification letter, Guardian Credit Union stated, “We take the privacy and security of personal information in our care very seriously and sincerely regret any inconvenience or concern this event may have caused.”
