Nvidia has reportedly been "completely compromised" by a cyber attack.
As reported by The Telegraph, parts of the graphics chip business - America's largest microchip company - have been offline for two days.
A malicious network intrusion has affected Nvidia's internal systems, including email and developer tools, which have suffered outages since last week.
It's so far unclear whether any data has been stolen from Nvidia - be it internal data or customer data - or if the attack has been solely to disrupt systems.
"We are investigating an incident. We don't have any additional information to share at this time," an Nvidia spokesperson told The Telegraph.
Earlier in the week, an Nvidia spokesperson told Bloomberg: "Our business and commercial activities continue uninterrupted. We are still working to evaluate the nature and scope of the event and don't have any additional information to share at this time."
Bloomberg also reports the attack is not connected to the war between Russia and Ukraine, despite governments and companies globally on high alert for potential cyber attacks.
Cyber security expert Alan Woodward told The Telegraph that Nvidia likely shut down its systems to avoid further damage.
"The ultimate concern is that somebody may have put something in one of the software updates," Dr Woodward said.
"They'll be going through trying to make sure to see if there's any indication that anything has been changed in their software that they then shipped to their clients."
Last year a list of forthcoming PC games were datamined and leaked from Nvidia's cloud gaming service GeForce Now, many of which have now been released or confirmed.