Elon Musk's artificial intelligence company xAI is raising $15 billion from investors, sources familiar with the matter told CNBC's David Faber.
Musk later called the news "False" in a post on his social media platform X.
The funding adds another $5 billion to the $10 billion round CNBC reported on in September, which valued the startup at $200 billion.
Sources told CNBC that a lot of the money in this $15 billion round will fund graphic processing units that underpin large language models
Artificial intelligence startups have reached sky high valuations in recent months as they raise massive amounts of capital to power seemingly endless demand for foundational models.
In September, AI startup Anthropic closed a $13 billion funding round that roughly tripled its valuation from March.
Sam Altman's OpenAI in October closed a $6.6 billion share sale at a $500 billion valuation. Last month, Reuters reported that the ChatGPT maker was prepping for an IPO that could value it at $1 trillion.
Musk's AI venture has repeatedly stirred controversy, including with its rapid build-out of large, power-hungry data centers in Memphis.
The data centers have used natural gas-burning turbines as a power source, emissions from which contribute to air quality problems in the area, according to local researchers.