Lightmatter announced it has raised a $400 million Series D, valuing the company at $4.4 billion and bringing the total capital raised to date to $850 million. The round was led by new investors advised by T. Rowe Price Associates, Inc. with participation from existing investors, including Fidelity Management & Research Company and GV (Google Ventures).

Lightmatter will ready Passage™ for mass deployment in partner data centers, enabling the scaling required for sustained AI innovation.