A mysterious new AI model called Ox Alpha has driven certain corners of the internet into a frenzy of speculation about who actually built it.

The free model was released on OpenRouter on Thursday, where it was described as “a reasoning model designed for coding, sustained agentic work, and production workload.” On X, Stripe CEO Patrick Collison (whose company is acquiring OpenRouter) described Ox Alpha as “very impressive.”

So who’s actually behind Ox Alpha? The OpenRouter listing described it as a “stealth model” and said it was “developed and operated by a third-party provider who has chosen to remain anonymous during this preview.”

Unsurprisingly, much of the speculation has revolved around China. AI analyst Andrew Curran posted on Friday that the initial speculation focused on the GLM models developed by Chinese company Z.ai, but “this morning people seem less sure of anything.”

Similarly, an article on Wccftech first suggested that the evidence pointed to GLM, but an update suggested that Ox Alpha could be an unreleased version of Microsoft’s MAI. And on Reddit, there’s at least one post declaring that Ox Alpha “can’t be the Chinese,” while another expressed “high confidence” that it is, in fact, Chinese.