U.S. Bancorp in Minneapolis has disclosed a data breach involving credit card customers.
The $370 billion-asset company filed a notice with the California Attorney General’s office stating that some personal data was compromised when a vendor accidentally shared a file with the information. The event is believed to have taken place on Sept. 27.
A company spokesperson told NBC News that about 11,000 cardholders were impacted.
The shared data included names, Social Security numbers, closed account numbers, and outstanding balances.
U.S. Bancorp said the error was discovered immediately and that file recipients cooperated to secure the data.
The company is offering cardholders two years of free access to online credit monitoring. It also recommended that customers “remain vigilant” and place a fraud alert on their credit files.