A Microsoft web page confirmed that OpenAI has been using Looped Transformers in the GPT-6 series, validating prior reporting by The Information. The documentation indicated that GPT-6.1 Sol utilizes two inference passes, a reduction from three.

The article notes that GPT-6 and GPT-6.1 share the same pre-trained base model weights but differ in post-training, with GPT-6.1 employing one fewer loop.

Microsoft subsequently updated the web page to remove this information.