Tax systems back up, failure still under investigation

The IRS announced on Feb. 4 that its systems were back online after the electronic filing and "Where's My Refund?" tools went down on the afternoon of Feb. 3.

"IRS teams worked throughout the night and around the clock on this system outage," IRS Commissioner John Koskinen said in a statement. "Our processing systems are back in business. Taxpayers should see little, if any, impact on their tax returns or refunds."

The IRS said it had restored systems by 5 p.m. EST on Feb. 4 and was investigating the outage.

The agency initially blamed a hardware failure and said 90 percent of taxpayers should still receive refunds within 21 days after filing.

Third-party tax preparers held onto electronic returns during the outage and have resumed routing them to the IRS, the agency said.

Rep. Jason Chaffetz (R-Utah) said in an appearance on the Fox Business Network that the multiday outage might have been related to a hack of the IRS. However, a spokesperson for Chaffetz was unable to offer substantiation.

In its latest statement, the IRS reiterated its assertion that the malfunction was due to a hardware failure. An IRS spokesperson did not immediately respond to requests for elaboration on that failure, and it's unclear whether the IRS will release a play-by-play account once an investigation has been completed, as other agencies hit by hardware malfunctions have done.