A new European Central Bank (ECB) gauge of Reddit investor sentiment is associated with next-day S&P 500 returns, especially during downturns, giving researchers a more frequent measure than surveys.
Financial stability analyst Fabian Wagner and financial stability expert Julian Metzler developed the Reddit Retail Investor Sentiment Indicator, or R-RISI, and described it in an ECB blog post published Nov. 12. Their working paper examines posts from major investing and crypto-related subreddits between 2015 and April 2026.
OpenAI’s ChatGPT 5.1 classifies posts as positive, negative or neutral, and identifies topics and stock tickers or alternative asset classes. The blog lists equities, macroeconomics, commodities, geopolitics and crypto-assets among the topics. To account for engagement, the researchers weight posts using Reddit scores and comment counts.
The researchers calculate daily z-scores for the weighted positive and negative post series using a rolling 365-day window. A z-score shows how far a value sits from that series’ average over the period. They subtract the negative series from the positive one, then smooth the difference over seven days; the indicator is reported weekly.
The working paper says R-RISI aligns with established sentiment measures and contains statistically significant short-term information for market prices. The authors report an association between changes in the indicator and next-day S&P 500 returns, particularly when markets are declining. The finding describes a relationship; it does not show that Reddit discussions cause price changes.
The researchers also examine the gauge by discussion topic. They say macroeconomic posts weighed on sentiment during the COVID-19 market shock, while tariff-related discussion pushed it lower during market turmoil in April 2025.
The authors describe the gauge as a more frequent source of information than surveys, writing that it offers “higher frequency information than survey-based indicators.” Because its inputs are post text and engagement, R-RISI reflects sentiment expressed online; it cannot confirm whether posters hold or trade the assets they mention. That distinction is an inference from the method the researchers describe. The ECB blog says the authors’ views may differ from those of the ECB and the Eurosystem.
