Mystery AI model Ox Alpha revealed as Zhipu's GLM-5.3-Flash, stocks jump
The internet's guessing game over the anonymous AI model Ox Alpha ended on Wednesday when China's Zhipu AI confirmed it was behind the release, identifying it as a preview of its new GLM-5.3-Flash model. The announcement came after days of speculation that had propelled the model to top usage rankings and sent the company's shares surging more than 12% in Hong Kong.
Zhipu, which also operates under the name Z.ai, said in a blog post that Ox Alpha had been a free-to-use preview of GLM-5.3-Flash, appearing on model marketplace OpenRouter and developer platform OpenCode on August 20. The company ran the model anonymously to gather user feedback.
"Before release, we tested GLM-5.3-Flash anonymously as ox-alpha on OpenCode and OpenRouter to gather user feedback," Z.ai wrote. "It quickly became the most popular model of the week — with all of this traffic served on Chinese AI chips."
Domestic chip milestone
The reveal came with a notable technical claim: Zhipu said GLM-5.3-Flash ran entirely on a cluster of 100,000 domestically produced chips. The company said the model processed 62 trillion tokens before its official release, and on OpenRouter alone it handled more than 11 trillion tokens in its first three days, which Zhipu called the platform's biggest launch to date.
OpenRouter data from Thursday showed the model ranked first among coding systems, accounting for 10.3 trillion tokens — nearly 31% of its total weekly volume. Zhipu's shares closed 12% higher at HK$1,160 in Hong Kong on Thursday following the news.
The domestic chip detail drew particular praise from Chinese users on the social media platform Weibo. A user from Sichuan province lauded Z.ai for using domestically produced chips, saying the example "shows that Chinese chips can efficiently support large-scale AI use." Another user from Beijing called the model "amazing, delivering strong performance at a low cost." A second poster from Sichuan described it as "ridiculously cheap."
The announcement triggered a wave of enthusiasm on Weibo. As of noon on Thursday, a hashtag about Z.ai claiming ownership of Ox Alpha had thousands of posts, was ranked among the top 20 hot topics, and had been viewed more than 13 million times in under 24 hours, according to Business Insider Africa. Over the weekend, Weibo users had nicknamed the model "Niu Lai," the title of a Chinese animated movie released in August.
Global recognition and speculation
The model's performance also drew international attention before its identity was known. Stripe CEO Patrick Collison, whose company is acquiring OpenRouter, said on X that he tried the model and found it "very impressive."
Before Zhipu's announcement, the model's anonymity had fueled speculation. OpenRouter's listing described Ox Alpha as a "stealth model," developed and operated by "a third-party provider who has chosen to remain anonymous during this preview." The company said it was only routing requests to the model and was not its developer, owner, or provider, with both input and output pricing listed at $0.
Early theories pointed toward China's Z.ai, given the GLM family connection, while others speculated about Microsoft and an unreleased MAI model. The model's specs — a reasoning model for coding, long-running AI agent tasks, and production workloads with a 1-million-token context window — had impressed developers during the preview.
Competitive context
Zhipu's launch comes amid a flurry of open-weight model releases from Chinese AI labs. Moonshot AI launched Kimi K3 in July, an open-weight model that rivals capabilities of models from OpenAI and Anthropic at lower cost. Alibaba released its latest Qwen3.8-Flash-Next model on Wednesday, an efficiency-focused, open-weight model that promises lower training and inference costs.
With the mystery resolved, Zhipu has positioned GLM-5.3-Flash as a flagship demonstration of both model capability and domestic chip infrastructure. The strong reception — both on global platforms and among Chinese users — suggests the strategy of an anonymous preview successfully built anticipation before the official unveiling.