A new study from Columbia University has revealed that trading activity on Polymarket, a prominent prediction market platform, has been significantly inflated by artificial market manipulation known as ‘wash trading’. Researchers discovered that roughly 25% of the total buy-and-sell volume in the past three years could be attributed to this deceptive practice, where users quickly buy and sell contracts to create the illusion of increased market activity. The study, titled ‘Network-Based Detection of Wash Trading’, identifies patterns of artificially created trading behavior across Polymarket transactions from 2022 to 2025. By using network analysis techniques, researchers found that this inflated activity fluctuated significantly over time, reaching a peak of almost 60% in late 2024 before declining to roughly 20% by October 2025. Sports-related markets showed the highest prevalence of artificial trading, accounting for nearly 45% of detected volume, while election and political markets were less affected. This study does not suggest that Polymarket itself engaged in or encouraged such activity but highlights how the decentralized nature of prediction markets, which enable users to trade event-based contracts using cryptocurrency, can be susceptible to manipulation from individuals seeking to simulate liquidity or attract attention to specific markets. Polymarket, operating on the Polygon blockchain, has gained significant popularity in recent years due to the growing interest in crowd-driven forecasting tools. The study’s findings emphasize the need for more robust monitoring systems within blockchain-based financial platforms to detect and deter wash trading activity. This is particularly crucial as prediction markets gain wider acceptance in mainstream finance and face increasing regulatory scrutiny.