The Obama Administration has decided not to publicly name China as the perpetrator of the massive cyber attack against the Office of Personnel Management.
According to the Washington Post, this is partially because they are hesitant to release the evidence they have put together on the OPM hack.
Furthermore, it looks like the administration has decided against directly retaliating against China, or trying to corrupt or destroy the stolen OPM records.
A senior official stated, “we have chosen not to make any official assertions about attribution at this point.” This is interpreted largely as a safeguard, because an attribution of that nature could mean that the U.S. would have to expose details about our own eavesdropping and espionage programs.