Judging by the tweet containing the link to the file, the leak was a reaction to FBI's last week's statement that the arrest of LulzSec members has effectively defanged Anonymous.
"The movement is still there, and they're still yacking on Twitter and posting things, but you don't hear about these guys coming forward with those large breaches," stated Austin Berglas, the assistant special agent in charge of FBI's cyber division in New York. "It's just not happening, and that's because of the dismantlement of the largest players."
"The central banking and finance system has systematically defrauded the planet and bears responsibility for unfathomable death and misery," the hacker group wrote by way of explanation of the leak. "As the FBI and DOJ have proved themselves incapable or unwilling to prosecute the institutional kleptocrats, we will step up to the plate."
According to Bloomberg, the Federal Reserve along with law enforcement are investigating the leak and, as far as they can tell so far, the information was stolen during the Federal Reserve breach in February 2013.
At the time, the a Federal Reserve spokesman confirmed the breach and the exfiltration of a file containing names, mailing addresses, business phone and mobile phone numbers, business email addresses, and fax numbers of various banks' employees that were contact persons in case of a natural disaster.
He also confirmed that the breach was executed by exploiting a "temporary vulnerability in a website vendor product."
Then as well as now critical operations of the Federal Reserve system were not compromised.