Shares of Z.AI, also known as Zhipu AI or Z.ai, rose 9.7% to HK$1,130.0 by 01:43 ET (05:43 GMT) on Thursday after the Chinese artificial intelligence company confirmed that it developed the previously mysterious Ox Alpha model. Zhipu told Bloomberg that Ox Alpha is a new iteration of its GLM series, ending speculation about the model's origins. The company plans to release the model's weights, enabling developers to build applications and services on top of it. Ox Alpha appeared anonymously on AI platform OpenRouter on Aug. 20 and quickly reached the top of its usage rankings, drawing attention for coding, reasoning and agentic tasks. Recent reports said it supports text, image and video inputs and has a context window of about 1 million tokens. The confirmation adds to developments underscoring the rapid progress of Chinese AI developers, which are increasingly challenging established U.S. models with lower-cost and open-weight systems.