ECB AI Tool Tracks Reddit Investor Sentiment

The European Central Bank has introduced an AI-based indicator that measures retail investor sentiment by analyzing millions of posts from investing-focused Reddit communities. Researchers used ChatGPT-5.1 to classify posts and track the subjects investors discuss, producing a daily measure that offers more timely information than survey-based indicators. The ECB says shifts in the index are associated with next-day market returns, with the relationship particularly relevant during market downturns, and that the measure can be examined across asset classes and selected securities.