A recent study has shed light on the inner workings of prediction markets, suggesting that a mere 3% of traders are responsible for the accuracy of market predictions. This discovery challenges the long-held notion that the collective knowledge of the crowd is the driving force behind prediction markets.
The study, conducted by researchers from the London Business School and Yale, analyzed over 1.7 million accounts and $13.76 billion in trading volume on Polymarket, revealing that a small group of informed traders consistently move prices in the right direction, while the remaining 97% of traders tend to lose money. The researchers employed a novel approach to distinguish between skill and luck, rerunning each trader's bets 10,000 times with the direction determined by a coin flip.
The results showed that only 12% of the biggest winners by raw profit consistently outperformed the benchmark, indicating that skill plays a significant role in their success. Furthermore, the study found that the activity of skilled traders improves market accuracy, particularly in the final stretch before resolution, and that they are the first to react to new information.
However, the study also raises concerns about the potential for insider trading, citing a concrete example of three newly created Polymarket accounts that placed unusually large bets on a contract related to the removal of Nicolás Maduro from power in Venezuela, collectively making over $630,000. While insider trades are rare, they can have a significant impact on prices, highlighting the need for vigilance in maintaining the integrity of prediction markets.