Stanford HAI released its 2026 AI Index Report on April 13, finding that the US-China performance gap has effectively closed — the two countries' models trade places at the top of arena benchmarks with no consistent leader. The Foundation Model Transparency Index average dropped from 58 to 40 as frontier labs have stopped disclosing dataset sizes, training durations, and parameter counts. On the adoption side, generative AI reached 53% global population use within three years — faster than the PC or the internet — though uptake tracks closely with GDP per capita. US public trust in government AI oversight sits at 31%, the lowest of any country surveyed, while South Korea has surpassed all others in AI patents per capita.