Stanford's Human-Centered Artificial Intelligence Institute (Stanford) has published its 2026 AI Index Report, which covers technical performance, investment, workforce effects, and public sentiment. The report found that Generative AI reached 53% adoption among the global population within three years of ChatGPT's launch, faster than either the personal computer or the internet. This is the ninth annual AI Index. In terms of capability, frontier models now exceed human performance on PhD-level science questions and in competitive mathematics. Global corporate AI investment reached $581 billion in 2025, up 130% from the previous year, and over 90% of frontier models come from private companies. However, employment among software developers aged 22 to 25 has dropped by nearly 20% since 2024. The most capable models now disclose the least about their training data, parameters, and methods.