After a weekend of speculation, Bloomberg reported that Z.ai, the company behind the GLM series, has acknowledged it created Ox Alpha — the anonymously shared open-weight model that had appeared on OpenRouter and was quickly ranking highly on benchmarks and leaderboards.
Z.ai said Ox Alpha is the latest iteration of its GLM line. The company describes the model as “a reasoning model designed for coding, sustained agentic work, and production workloads. It is suited for long-horizon software engineering, complex reasoning, and workflows that combine text with visual context.”
Z.ai also announced it will release the model weights on Wednesday, after which developers will be able to build on top of the base model. Publishing weights is a significant step in model distribution because it enables direct fine-tuning, local deployment, and third-party development.
The arrival of Ox Alpha and the decision to release its weights underscore the growing competition from capable, lower-cost models developed in China that could capture market share from expensive frontier providers such as OpenAI and Anthropic. Earlier this month, Z.ai released GLM-5.3, which has competed with Anthropic’s Fable 5 on some benchmarks.
TechCrunch has reached out to Z.ai for further comment.
