Since 2023, a measurable gap has emerged between the most capable AI models from the US and China. Chinese models reach the capabilities of their US counterparts with an average delay of seven months, as an analysis of the Epoch Capabilities Index (ECI) shows. The range spans from a minimum of four to a maximum of 14 months – a gap that persists throughout development since early 2023. Every model that has reached the frontier of AI capabilities since 2023 originates from the United States.