The office has been in contact with JPMorgan Chase about the incident since it first surfaced in August, the person said.
On Thursday, JPMorgan revealed the scope of the breach, saying names, addresses, phone numbers and email addresses of the holders of some 83 million households and small business accounts were exposed when its computer systems were compromised by hackers.
Other state attorneys general are "very concerned and sharing information" about the incident amongst themselves, another source said, although a multi-state group to probe the matter has not yet formed.
(Reporting By Karen Freifeld; Editing by Meredith Mazzilli)
By Karen Freifeld