China's Moonshot unveils world's 'largest' open AI model, Kimi K3, closing in on US rivals

China’s Moonshot has unveiled Kimi K3, an open-weight artificial intelligence model the company says is the world’s largest of its kind, as Chinese developers race to close the gap with leading US AI firms.

According to a monitored public feed from Dawn Tech, the startup announced the model on Friday, describing it as a 2.8 trillion-parameter system designed for advanced reasoning, long-range coding and knowledge-intensive work. Moonshot said Kimi K3 is the first open-weight model to come close to the 3 trillion-parameter level, putting it among the biggest AI systems publicly available to developers.

The company also said Kimi K3 includes a one million-token context window, which allows it to take in and work with far more information in a single prompt than earlier generations of models. Moonshot said the system can handle long-horizon coding tasks with limited human supervision and incorporates two architectural changes aimed at improving computing efficiency.

Moonshot claimed Kimi K3 delivered performance that approached Anthropic’s frontier Fable model and exceeded several other prominent systems on specific tasks. In particular, the company said the model performed strongly in GPU kernel optimisation, a technical area focused on making better use of AI hardware and reducing latency.

Third-party evaluations cited in the feed also pointed to competitive results. Arena.ai ranked Kimi K3 first in a benchmark for web interface-building, while Vals AI placed it second overall behind Fable 5 and ahead of GPT-5.6 Sol. Artificial Analysis said the model’s performance was comparable to OpenAI’s GPT-5.5 and Anthropic’s Claude Opus 4.8, especially on tests that measure multi-step reasoning.

The launch adds to signs that China’s open AI ecosystem is advancing quickly. Companies including Moonshot, Z.ai and MiniMax have been rolling out larger and cheaper models, challenging the idea long held in Western markets that Chinese AI developers lag US rivals by months.

The timing also comes after a reported disruption in the US market, with Anthropic’s Fable and Mythos models said to have been abruptly withdrawn by the US government over security concerns about a month before Moonshot’s announcement. The feed said that development has drawn more attention to the speed at which Chinese firms are expanding their capabilities.

The market reacted sharply in Hong Kong, where shares of domestic AI names fell after the announcement. By midday, Zhipu was down 21.9% and Minimax was down 13.8%, according to the feed.

Moonshot’s release also reflects a broader shift toward faster product cycles in China’s AI sector. The feed noted that Z.ai’s GLM-5.2 recently drew attention for its benchmark performance, while MiniMax is developing a 2.7 trillion-parameter model and preparing a frontier-level multimodal system called H3.

The company behind Kimi K3 is backed by major Chinese tech investors, including Alibaba and Tencent. Bloomberg previously reported that Moonshot was seeking fresh funding ahead of a possible Hong Kong listing, though that report was separate from Friday’s announcement.

This report is based on a monitored public feed. Source attribution: Dawn Tech. Source: Dawn Tech - https://www.dawn.com/news/2016173/chinas-moonshot-unveils-worlds-largest-open-ai-model-kimi-k3-closing-in-on-us-rivals