Research Reveals That Only a Small Group of Informed Traders Drive the Accuracy of Prediction Markets

A recent scandal involving a Green Beret who was arrested for betting on a classified US raid may be more than just an isolated incident. According to a new study, it may be an example of the small group of informed traders who actually influence prices on platforms like Polymarket, while the majority of users end up losing money. The study, which analyzed over 1.7 million accounts and $13.7 billion in trading volume, found that just 3% of traders are responsible for most price discovery, meaning they are the ones who drive prices towards the correct outcome. These traders consistently make accurate predictions and move prices in the right direction, while the remaining 97% of traders mostly do not. The study's authors used a novel approach to distinguish between skill and luck, rerunning each trader's bets 10,000 times with the direction of the bet determined by a coin flip. The findings show that among the biggest winners, only 12% consistently outperformed the benchmark, and many apparent winners did not sustain their performance over time. The study's results have significant implications for our understanding of how prediction markets work, suggesting that it is the informed minority, rather than the crowd, that drives market accuracy. The activity of these skilled traders improves market accuracy, particularly in the final stretch before an event is resolved, and they are also the first to react to new information. However, the study also raises important questions about the risk of insider trading and the use of non-public information in prediction markets.