A Polymarket trader says he lost roughly $500,000 on a market that asked whether MicroStrategy — now called Strategy — would sell any Bitcoin by May 31. The market resolved to 'No' even though Strategy sold 32 BTC, worth about $2.5 million, between May 26 and May 31. The sale was confirmed in an SEC filing on June 1, one day after the market's cutoff.
What the trader claims
The trader argues the rules only required a sale within the timeframe, not a public confirmation. He says he increased his position after the SEC filing while the market was still open, betting that the disclosure would trigger a 'Yes' resolution. Polymarket instead added a post-hoc clarification stating that confirmation achieved outside the market's timeframe — in this case, after May 31 — does not qualify for a 'Yes' outcome.
That clarification came after the fact. The trader based his initial bet on on-chain data showing Strategy had deposited roughly $30 million worth of Bitcoin into Coinbase Prime about a week before the deadline.
How resolutions get contested
Polymarket's resolution process allows disputes by posting a bond. That triggers a vote by UMA token holders, who decide the final outcome. Some users claim those votes can be swayed by large UMA holders — so-called whales — creating a risk of manipulation. The trader hasn't said whether he'll pursue a dispute, but the mechanism is in place.
What happens next
The market is resolved, but the dispute window remains open. If the trader or anyone else posts the required bond, UMA token holders will have the final say. That process could take days. For now, the trader is left arguing that the sale happened on time — and that Polymarket changed the rules after the fact.
