Stanford study says 5-minute Bitcoin prediction markets enable settlement manipulation

Researchers found that Polymarket’s five-minute Bitcoin prediction markets create incentives to manipulate spot prices around contract settlement, proposing longer settlement windows as a potential fix.

Researchers at Stanford University and Singapore Management University found that Polymarket’s five-minute Bitcoin prediction markets create incentives for traders to manipulate spot prices around settlement, allowing sophisticated participants to profit at the expense of retail traders.

The study examined contracts in which traders bet on whether Bitcoin’s price would end above or below a predetermined level after five minutes. Because the contracts settle using Chainlink price feeds based on Bitcoin’s price at the end of each trading window, traders have an incentive to influence the spot market immediately before settlement.

Analyzing trading activity before and after Polymarket introduced the contracts in July 2024, the researchers found sharp increases in Bitcoin spot-market order flow just before settlement, followed by rapid price reversals, which were consistent with settlement-price manipulation.

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