A Columbia study found that up to 60% of Polymarket’s volume may stem from wash trading, raising new concerns about artificial activity in prediction markets.
The rapid growth of the prediction market Polymarket may not be entirely organic but instead inflated by artificial trading activity, according to research published by Columbia University.
In an 80-page paper titled “Network-Based Detection of Wash-Trading,” which has not yet undergone peer review, Columbia researchers identified extensive wash-trading activity on Polymarket beginning in July 2024. That month, they found that wash trades accounted for nearly 60% of the platform’s total trading volume.
“This activity persisted through late April 2025 before subsiding substantially, and once again increased to about 20 percent of volume in early October 2025,” they wrote.
