76,000 California AmEx users were victims of a breach by Anonymous

American Express is in the process of notifying residents that their credit card information was posted online in March, during a protest against financial firms for, as the hacktivists put it, “enslaving” people.

“At this time, we believe the recovered data may include your American Express Card account number, the card expiration date, the date your card became effective and the four digit code printed on the front of your card,” AmEx said in a letter to the California Attorney General's Office.

Social Security numbers were not affected by the compromise. AmEx has no evidence of any unauthorized activity on accounts related to the incident.

58,522 of the victims also had their names posted with the card information.

In March, the hacker collective Anonymous Ukraine claimed to have released more than 7 million records maintained by various credit card companies.

AmEx said it discovered that the hacktivists posted several large files containing personal information when the UK’s National Crime Agency brought it to the company’s attention, on March 25.

ThreatWatch is a regularly updated catalog of data breaches successfully striking every sector of the globe, as reported by journalists, researchers and the victims themselves.