Stanford Research: Signs of Manipulation in the Polymarket Five-Minute Bitcoin Betting Market

According to Bloomberg, researchers at Stanford University have found signs of manipulation in the Polymarket five-minute Bitcoin betting market. The study analyzed contract data over approximately two months and discovered repeated one-way trading pulses on the Binance exchange that briefly affected Bitcoin prices just seconds before the betting ended, benefiting those with aligned positions. The researchers referred to this pattern as "temporary manipulation to drive up spot prices" and pointed out that such contracts have structural vulnerabilities—participants can influence the outcome by trading the underlying asset itself that determines win or loss.

A Polymarket spokesperson stated that the platform uses multiple independent price oracles to ensure accuracy and plans to transition some markets to a settlement method using longer time windows next year to enhance market integrity. The study estimates that suspected manipulators profited about $8.2 million over two months, primarily from losses incurred by retail traders. Similar patterns are not evident in the 15-minute market, where longer time windows make it more difficult to influence outcomes.