Can Polymarket change a market's rules after you buy?
Yes. Polymarket can add a clarification to a market's rules, move its end date or change its resolution source while the market is open, and it has done so on markets with millions of dollars in positions. Since I started recording on Oct 31, 2026, I recorded 62 on Polymarket (1 rules edit, 18 disputed outcomes, 42 date changes, 1 title change).
Cases on the record
- MicroStrategy market, June 1, 2026. A clarification tied resolution to the date a sale was disclosed. The top Yes holder lost about $500,000 (DeFi Rate).
- The same dispute, after settlement. A clarification cleared about $3.8M of Yes positions across 1,838 accounts (KuCoin News). Traders sued for at least $797,198 and asked a court to stop Polymarket from changing settlement rules after outcomes are known (DailyCoin).
How often it happens in my record
Most Polymarket edits I see are not clarifications. 1 rules edit, 18 disputed outcomes, 42 date changes, 1 title change. Moved end dates are the most common, often on sports and esports markets where a start time shifts. Edits to the rules text are rarer and matter more.
| Kind | Polymarket | Kalshi |
|---|---|---|
| Clarification added | 0 | 6 |
| Rules edited | 1 | 10 |
| Resolution source changed | 0 | 0 |
| Outcome disputed | 18 | 0 |
| Dates changed | 42 | 3 |
| Title changed | 1 | 1 |
| All edits | 62 | 20 |
How to find out before it costs you
- Before you buy, open the market's page here and read its history. If the rules were edited, the page shows every version.
- If you hold it, press Watch. Watched markets are checked every 5 minutes; others are reread every hour or two.
- Read the exact words, not the summary. The change page marks removed words in red and added words in green.
Latest edits to Polymarket rules text
- Will Anthropic's valuation hit (HIGH) $1.75T by December 31?: Rules edited, Nov 4, 2026, 00:10 UTC.
More on the mechanics: what a clarification is. All edits: changes feed.
Numbers as of Nov 4, 2026, 19:11 UTC; they refresh every 6 hours.