Traders Sue Polymarket and CEO Shayne Coplan Over Alleged Rule Change That Flipped Winning Bitcoin Bets

Two Polymarket traders have filed a lawsuit in New York state court accusing the prediction platform of retroactively changing the rules on a BBTC$64,137.00▲0.94%-sale market, turning their winning “Yes” positions into a $797,000 loss.

Plaintiffs William Wood and Thomas Bush filed the complaint in the Supreme Court of the State of New York against Polymarket, its holding entities, and CEO Shayne Coplan personally. The dispute centers on a market asking whether Strategy — formerly MicroStrategy — would sell Bitcoin. Wood and Bush held “Yes” positions and argue the market should have resolved in their favor after Strategy disclosed a Bitcoin sale. Instead, Polymarket settled the market as “No,” according to Decrypt’s report on the complaint.

The core allegation is damaging and simple: after the settlement, Polymarket issued a “clarification” that the plaintiffs say changed the standard used to resolve the market. They claim the platform added a rule after the fact — one that flipped a winning bet into a losing one. Both Yahoo Finance and Decrypt confirm the framing: “The plaintiffs say Polymarket added a rule after the fact, turning their winning ‘Yes’ bet on Strategy’s Bitcoin sale into a loss,” as reported by Decrypt.

The market carried roughly $797,000 in total settlement value, per DailyCoin. Not a catastrophic sum for a platform that has processed hundreds of millions in volume — but large enough to matter, and the principle at stake is larger still. Prediction markets live and die on the credibility of their resolution process. If traders believe the house can rewrite the rules once the outcome is known, the entire mechanism breaks.

Naming Coplan personally is a deliberate escalation. The suit doesn’t stop at the corporate veil; it targets the individual at the top, signaling that the plaintiffs intend to press claims that reach beyond the platform’s holding structure. The choice of venue matters too. New York state civil court, not a federal regulator or an arbitration panel — the kind of private dispute-resolution framework platforms typically prefer. This is a public fight, by design, in front of a state judge and jury pool.

The underlying real-world event is not seriously in dispute. Strategy’s largest-ever Bitcoin sale — 3,588 BTC for $216 million — was the transaction the market was built to predict. The fight is over what the resolution criteria actually required, and whether those criteria were in place when traders bought their positions or were constructed after the fact to justify a “No” outcome. That distinction is the entire case.

The lawsuit also lands amid broader political and regulatory pressure on Polymarket. A Wall Street Journal report noted that two senators — one Republican, one Democrat — called for a federal probe of the platform over what they characterized as “fake bets.” The timing is not incidental. A civil suit alleging retroactive rule changes and a bipartisan Senate call for a federal investigation, arriving in the same window, create a compounding narrative that Polymarket now has to manage on multiple fronts at once.

The market backdrop sharpens why high-stakes prediction disputes carry weight right now. Bitcoin is trading at $63,675, up 2.18% over 24 hours, with a market cap of $1.277 trillion. The Fear & Greed Index sits at 27 out of 100 — squarely in fear territory. When spot markets are jittery and sentiment is sour, traders gravitate toward derivatives and prediction markets as alternative ways to express views or hedge exposure. That makes the integrity of those venues more consequential, not less. A platform accused of moving the goalposts during a period of heightened anxiety isn’t operating in a vacuum; it’s operating in an environment where users are already on edge and less inclined to extend goodwill.

Polymarket’s model depends on a single proposition: that resolution follows the rules as written, not as rewritten. Wood and Bush allege that proposition failed. Whether a New York court agrees will shape not just the fate of a $797,000 market but the credibility standard the entire prediction-market sector gets held to. The case is in its earliest stages. No trial date has been set, and Polymarket has not publicly detailed its defense. The immediate question is whether the platform moves to push the case into arbitration — a common tactic for platforms whose terms of service include mandatory dispute-resolution clauses — or whether it fights the claims in open court.