Moonshot AI's Kimi K3 Is Now the Largest Open-Weight Model Ever Released

Moonshot AI released Kimi K3 on July 16, 2026, a 2.8 trillion parameter mixture-of-experts model benchmarked as competitive with top proprietary US systems. Full model weights followed on July 27, 2026, making the release genuinely open rather than a benchmark announcement with restricted access behind it.

At 2.8 trillion parameters, Kimi K3 is being described as the largest open-weight model ever released, a scale that puts it well past most previous open releases from any lab, Chinese or Western.

The release lands squarely in the ongoing race between Chinese open-weight labs and closed Western frontier labs. Moonshot AI's approach, publishing full weights rather than keeping the model behind an API, keeps pressure on the argument that the biggest, most capable systems have to stay closed to be commercially viable. Whether that pressure changes how Western labs handle their own release strategy is the thing worth watching over the next few months, not the raw parameter count itself.