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Mainstreet Credit Union Data Breach Lawsuit Investigation
Shamis & Gentile P.A., one of the nation's premier class action law firms specializing in data breach cases, is investigating the Mainstreet Credit Union data breach.
If you were affected by the data breach, your sensitive personally identifiable information may have been exposed, and you may be eligible for compensation.
About Mainstreet Credit Union
Mainstreet Credit Union is a member-owned, not-for-profit financial institution serving the Kansas City metropolitan area.
Founded in 1953, the credit union offers a variety of financial services, including checking and savings accounts, loans, mortgages, credit cards and online banking.
What Happened?
On Jan. 19, 2026, Mainstreet Credit Union discovered suspicious activity related to an employee’s email account.
The organization secured the account and began an internal investigation. Legal and forensic experts were engaged to determine the scope of the incident.
The investigation revealed that an unauthorized actor accessed one Microsoft 365 email account between Jan. 12 and Jan. 20, 2026. While it was not possible to determine exactly which emails or attachments were accessed, Mainstreet Credit Union conducted a thorough review of all emails and attachments stored in the compromised account.
On April 6, 2026, the review determined that personal information belonging to certain individuals was present in the account. Although currently unconfirmed publicly, the information exposed could pertain to names, Social Security numbers, and driver's license numbers.
On May 4, 2026, Mainstreet Credit Union began notifying affected individuals by mail. The total number of people affected in the United States was reported as 4,123.
You May Be Entitled to Compensation
If your personal information was exposed in the Mainstreet Credit Union data breach, you may be entitled to compensation. Lawyers are ready to help affected individuals understand their rights and pursue claims related to this incident.
To find out if you qualify and to join a lawsuit, complete the below form. Taking action now can help protect your rights and hold organizations accountable for safeguarding your sensitive information.
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