Mainstreet Credit Union Data Breach Exposes Member Information in Indiana

Mainstreet Credit Union in Indiana reported a data breach on May 4, 2026, where sensitive member information was exposed. The filing confirms that data including Full Name, Social Security Number, and Financial Account Number were compromised. This event requires affected individuals to closely monitor their financial and personal records for any unauthorized activity.

State: Indiana
Breach date: January 12, 2026
Reported: May 4, 2026

What may have been exposed

Full Name
Social Security Number
Financial Account Number
Date of Birth
Routing Number
Credit Score Information
Transaction History
Mailing Address

Mainstreet Credit Union, a financial cooperative based in Indiana, recently filed a data breach notification with state authorities. This official filing, dated May 4, 2026, confirmed a security incident that occurred on January 12, 2026, impacting the personal information of its members.

According to the public records, the types of data reported as exposed include Full Name, Social Security Number, Financial Account Number, Date of Birth, Routing Number, Credit Score Information, Transaction History, and Mailing Address. The comprehensive nature of this information suggests a significant compromise of sensitive member data.

The exposure of such detailed financial and personal identifiers can heighten the risk of various forms of financial fraud and identity theft. Individuals whose information was compromised may face potential threats to their financial security and personal privacy.

To help mitigate potential risks, affected individuals are generally advised to regularly review their bank and credit card statements for any unauthorized transactions. Monitoring credit reports from the three major bureaus (Equifax, Experian, and TransUnion) can also help detect suspicious activity promptly.

This information is based on public records filed with state regulators, providing a factual account of the reported data security incident. DataBreachInformation.com presents these details to assist individuals in understanding the specifics surrounding official breach notifications.

What to do if you were affected

Based on the categories of information reported in this filing, these steps can help limit the risk of identity theft and fraud.

Freeze your credit
Place a free credit freeze with Equifax, Experian, and TransUnion. A freeze blocks new accounts from being opened in your name and can be lifted anytime.
Watch your financial accounts
Review bank and card statements for unfamiliar activity and turn on transaction alerts. Report anything you don't recognize to your bank right away.
Stay alert to targeted scams
Be cautious of calls, texts, or emails that reference this breach. Legitimate organizations won't ask you to confirm sensitive details through an unsolicited message.
Keep your notification letter
Save the notice you received. It documents that your information was involved and is often needed to enroll in any credit monitoring offered or to join a related legal claim.

Source: Indiana Attorney General filing

Related data breach cases

Browse all Indiana data breaches View the full case directory