A recent study by researchers at Stanford University and Singapore Management University has revealed potential manipulation tactics in Polymarket’s bitcoin betting market, allowing some traders to extract $8.2 million by influencing Bitcoin's spot price on Binance before bets settled.
Mechanism of Manipulation
The study focuses on a specific contract on Polymarket, which pays out based on whether Bitcoin's price is higher at the end of a five-minute window. This contract relies on a Chainlink oracle that aggregates prices across leading exchanges. Researchers found that traders could manipulate the price by executing aggressive buy orders on Binance just seconds prior to the contract's closure. Their analysis indicated that the mid-price on Binance often deviated only slightly from the oracle price, allowing a small price push to alter the outcome of the bets.
In the crucial seconds before the contract settled, net order flow on Binance surged by approximately 50%. This surge typically reverted quickly, suggesting the price movements did not reflect genuine market activity. Among approximately 243,000 traders involved in the contracts, around 821 were identified as engaging in this pattern, profiting predominantly during manipulated cycles while retail participants suffered, bearing 93% of the losses.
Recommendations for Change
To mitigate such manipulation, the authors recommend extending the time window for settlement, noting that manipulation is less prevalent in Polymarket's 15-minute contracts. By increasing the time available for trades to settle, it would potentially diminish the effectiveness of such price nudges and create a fairer trading environment.
This article is for informational purposes only and does not constitute financial advice.
