Nvidia looked set to power higher on Thursday. Fellow artificial-intelligence chip companies Advanced Micro Devices and Broadcom were also gaining amid renewed spending excitement driven by OpenAI.

Nvidia shares were up 1.3% at $189.70 in premarket trading. Advanced Micro Devices was gaining 2.8% and Broadcom was rising 1.9%.

After a brief bout of skepticism about returns on AI investment, enthusiasm over the technology looks to be back in full swing. OpenAI this week released its Sora video-generation app, which soared up the most popular downloads on the Apple store, in similar fashion to its ChatGPT.

OpenAI on Wednesday said it would team up with South Korean chip companies Samsung Electronics and SK Hynix to boost the supply of advanced memory chips and build more data centers. SK Hynix gained 9.9% and Samsung Electronics finished 3.5% higher in local trading.

OpenAI is now valued at $500 billion following an employee share sale, according to multiple reports on Thursday. The company didn't immediately respond to a request for comment.

That kind of valuation from outside investors could help quell any concerns about Nvidia's own investment of up-to $100 billion in OpenAI, announced last month. That had raised some questions over the apparently circular nature of the deal, with much of the funding expected to eventually be spent on Nvidia's own hardware.

"Nvidia is poised to generate well over $600 billion in free cash flow over the next 3.5 years," wrote Melius Research analyst Ben Retizes in a research note. "We used to think they'd have no choice but to announce the biggest buyback program ever -- but now we wouldn't be surprised if just 20% of that cash went to buying back stock. Instead, [Nvidia CEO] Jensen [Huang] is going to use cash to invest in his ecosystem to help grease the AI flywheel."