A trader on Polymarket reportedly walked away with $233,000 after a high-risk weekend strategy in XRP-linked prediction markets, while automated bots took heavy losses. The trade quickly drew attention across crypto circles, and some observers described it as manipulation that should face disciplinary scrutiny.
The setup unfolded late on a Saturday night, a period when crypto trading activity is often light and even relatively small orders can move prices more than usual. CoinDesk contacted Polymarket for comment, though no response was included in the source material.
Buying the “UP” side into a thin market
According to details shared on X by pseudonymous trader PredictTrader, whose post circulated widely, an account identified as @a4385 began aggressively buying “UP” shares in a Polymarket contract tied to XRP. The market asked whether XRP would rise or fall between 12:45 PM ET and 1:00 PM ET on Jan. 17, 2026.
As the buying continued, the price of UP shares climbed to 70 cents. At the same time, XRP’s spot price on major exchanges actually weakened by about 0.3% during that window. That divergence mattered. Polymarket bots, built to post liquidity and react to pricing inefficiencies across linked markets, kept automatically selling more UP shares as the contract price rose, even while spot XRP drifted lower.
The result was a large position assembled at favorable levels: about 77,000 UP shares at an average cost of roughly 48 cents.
A $1 million XRP purchase just before settlement
The decisive move came right before the contract closed. According to the account shared publicly, a Binance wallet reportedly tied to the trader bought $1 million worth of XRP just two minutes before settlement. That order pushed XRP’s price up by about 0.5%, enough to flip the outcome in favor of the UP side.
Once the market settled, those winning shares could be redeemed for $1 each, locking in a large spread over the trader’s average entry price of 48 cents. The trader then sold the XRP bought on Binance, sending the spot price lower again.
Data source PolymarketHistory said the whole operation cost roughly $6,200, while the bots involved lost what amounted to a full year of profits overnight.
The same tactic was used across other weekend markets
The source says the trader repeated the approach in several other thin weekend markets, steadily draining liquidity from bots. Some systems adjusted and shut down. Others did not react in time.
The episode exposed a basic weakness in Polymarket’s automated market-making logic. These bots treated every price tick the same way, without accounting for trading volume, changing liquidity conditions, adversarial behavior, or the shift in incentives as settlement approached. In a low-liquidity environment, that left them vulnerable to a trader willing to coordinate prediction-market positioning with a move in the underlying spot asset.