Elon Musk-founded artificial intelligence startup xAI (previously X.AI) has filed with the SEC to raise up to $1 billion in an equity offering.

Of that, it has already raised $134 million from four undisclosed investors. Investors in X (previously Twitter) will also own 25 percent of xAI, but the two companies are separate.

Musk has acquired thousands of high-end Nvidia GPUs for xAI, and much of the newly raised funds will likely go to purchasing more.

The startup has developed its own large language model, Grok, which is currently smaller and less powerful than rival OpenAI's ChatGPT. However, the company says its system will "answer spicy questions that are rejected by most other AI systems," and benefit from real-time access to X.

Premium X subscribers have been promised access to Grok.

The company includes former DeepMind employee Igor Babuschkin, as well as former OpenAI, Google Research, Microsoft Research, Twitter/X, and Tesla staffers.

The fundraising comes as X has repeatedly seen its valuation downgraded from the $44bn acquisition price in 2022. In October, the company gave stock options to employees that valued it at $19bn.