OpLastResort, as it is also called, was created in the wake of Aaron Swartz's suicide.
Early Monday morning, Anonymous tweeted information about the hack, saying:
Now we have your attention America: Anonymous's Superbowl Commercial 4k banker d0x via the FED http://acjic.alabama.gov/documents/oops-we-did-it-again.html … #opLastResort #AnonymousThe website used by Anonymous is one belonging to the Alabama Criminal Justice Information Center (ACJIC). The page extension URL is titled, "oops-we-did-it-again." The site is currently down, but it was -- for a time -- live with the information.
A spreadsheet had been published on that page. It allegedly contained login information and credentials, IP addresses, and contact information of 4,000 American bank executives.
Included in that information was titles, addresses, phone numbers, emails, ID numbers, and hashed passwords. There's little reason to doubt the validity of Anonymous' data; it has a history of successful posts of such information.
It's widely believed that the information was obtained from computers belonging to the United States Federal Reserve. The loosely-knit hacker group previously targeted the United States Sentencing Commission (USSC) and defaced its website. In that hack, Anonymous cited the recent suicide of hacktivist Aaron Swartz as a "line that has been crossed."
Why target Feb. 4? Last Monday a House panel issued a letter to Attorney General Eric Holder with seven specific questions, and demanding answers regarding the aforementioned Aaron Swartz prosecution. Monday February 4, was the deadline for Holder to answer those questions.