Elon Musk's AI startup, xAI, seeks to raise up to $4 billion.

Special purpose vehicles (SPVs) are being used to bring investors together, but there are fees.

Musk aims to value xAI at $18 billion after this funding round.

xAI's main product, Grok, is claimed to outperform ChatGPT.

Despite its high valuation, xAI is still small, with few employees and resources.

xAI faces competition from other AI chatbots like ChatGPT and Microsoft's Copilot.