Did Russian State Sponsored Hackers Attack 5 US Banks To Retaliate Against Sanctions? Or the NSA Attacks Against Russia?

International Financial Law Prof Blog:

"At least one of the banks has linked the breach to Russian state-sponsored hackers, said one of the people. The FBI is investigating whether the attack could have been in retaliation for U.S.-imposed sanctions on Russia, said the second person, who also asked not to be identified, citing the continuing investigation."