xAI has announced the completion of its $6 billion Series C funding round, marking one of the largest private investments in artificial intelligence infrastructure. The round features participation from prominent investors including Andreessen Horowitz, BlackRock, Fidelity Management & Research Company, and strategic tech partners NVIDIA and AMD.
The funding announcement comes alongside revelations of xAI's ambitious technical achievements, headlined by Colossus, the company's proprietary AI supercomputer. Built using NVIDIA's full stack reference design, Colossus represents an unprecedented scale of deployment with 100,000 NVIDIA Hopper GPUs, and plans to double capacity to 200,000 GPUs in the near term.
The company's rapid infrastructure deployment stands out in the enterprise space. Colossus achieved full operational status in just 122 days—significantly faster than typical industry timeframes. More impressively, the system began running workloads only 19 days after initial server delivery, demonstrating remarkable operational efficiency.
Since its Series B in May 2024, xAI has launched several key initiatives, including Grok 2, their advanced language model, and the xAI API, which enables multi-region inference deployments for global enterprise access. The company has also introduced Aurora, a proprietary autoregressive image generation model, enhancing its multimodal AI capabilities.