China's Moonshot AI launches Kimi K3 to challenge US giants OpenAI, Anthropic

Beijing-based Artificial Intelligence (AI) startup Moonshot AI has launched Kimi K3, a 2.8 trillion-parameter model that stands as the largest open-weight AI system globally.

The release on Friday comes amid a technology race between the United States (US) and China, occurring one month after the American government withdrew Anthropic's Fable and Mythos models over security concerns.

According to Moonshot AI, Kimi K3 approaches the performance of Anthropic's frontier Fable model. While the company stated that K3 trails Anthropic's Claude Fable 5 and OpenAI's GPT 5.6 Sol in overall performance, it outperformed other tested models.

The system beat Claude Opus 4.8 and GPT 5.5 on benchmarks evaluating coding and general agents.

The model also features a 1 million-token context window, designed to process and retain data within a single prompt.

Moonshot AI stated K3 includes two architectural upgrades aimed at improving computing efficiency and executing long-horizon coding tasks with minimal human supervision.

Third-party evaluations support some of these claims. Arena.ai ranked Kimi K3 first in web interface-building tests. Vals AI placed the model second overall, behind Fable 5 but ahead of GPT-5.6 Sol.

Artificial Analysis reported that its performance matches OpenAI's GPT-5.5 and Claude Opus 4.8 on multi-step tasks.

Prior to this launch, the largest models in China were Meituan's LongCat-2.0 and DeepSeek's V4-Pro, which both feature 1.6 trillion parameters. Direct comparisons with US frontier systems remain difficult as companies like OpenAI and Anthropic do not publish parameter counts for models such as Fable, Mythos or GPT-5.5.

Lian Jye Su, chief analyst at Omdia, noted that Chinese models are gaining traction globally because they are cheaper to run. "They can be run at a fraction of the cost that OpenAI charges its clients," Su said, though he added that scale "doesn't necessarily mean you have the best performance by default".

Ryan Fedasiuk, a fellow at the American Enterprise Institute, noted that hosting the 2.8 trillion-parameter model locally is out of reach for most users, requiring "hundreds of thousands of dollars of computing equipment".

Following the announcement, shares of competing Chinese AI firms declined. Z.ai, which introduced its GLM-5.2 model in June, saw its stock drop 28% on Friday. MiniMax Group fell 16%, while Alibaba shares dropped 4%, despite a partnership announcement with Apple earlier in the week.

Founded in 2023, Moonshot AI is backed by Alibaba and Tencent. The company raised $2 billion at a valuation exceeding $20 billion in May.