[Report: The performance gap between U.S. closed-source frontier models and Chinese open-source weight models has narrowed to approximately 4.4 months] According to Ars Technica, Mozilla's latest *State of Open Source AI* report states that the performance gap between U.S. closed-source frontier models and Chinese open-source weight models has narrowed to approximately 4.4 months. Open-source models represented by Moonshot AI's Kimi K3 are only three points behind Anthropic Fable 5 in the Artificial Analysis Intelligence Index composite score, while their cost is approximately 30% of the latter. METR calculations show that the strongest closed-source models can reliably complete human expert tasks lasting about 12 hours, whereas the strongest open-source models can currently reliably complete tasks lasting about 7 hours. It is estimated that open-source models will catch up to the current closed-source level in approximately 4 months.