Polymarket's ladder on whether the U.S.-Iran ceasefire holds fell across every expiry on Wednesday afternoon, then recovered part of the drop overnight. The Oct. 24 contract bounced back most; later expiries recovered a third to about half.
The prediction market on the U.S.-Iran ceasefire does not ask whether the region is calm. It asks something narrower, and Wednesday showed why that wording matters.
Polymarket's contracts on whether the ceasefire "continues through" a series of dates resolve to No if the United States takes a qualifying military action against Iran by the deadline. Under the rules, that means U.S. air strikes or surface-to-surface missile strikes that directly hit Iranian territory. Intercepted munitions, ground incursions, cyber operations, artillery and threats do not count. Attacks by other parties, on ships or on Saudi Arabia, do not count either.
The afternoon drop
Between 2 p.m. and 5 p.m. Eastern on Wednesday, every expiry fell sharply. The contract for Oct. 24 dropped from 93.5 cents to a low of 72 cents. The Oct. 31 contract fell from 81.5 cents to 67 cents, Nov. 8 from 70 cents to 52.5 cents, Nov. 15 from 58.5 cents to 42.5 cents and Nov. 30 from 46.5 cents to 34.5 cents. Prices are market-implied probabilities, so a 72-cent price means traders put the chance of the ceasefire holding through Oct. 24 at about 72%.
The steepest leg, between 3 p.m. and 4 p.m., matched a report by Iranian state media at about 3:26 p.m. of explosions in the Sirik area of Hormozgan province, on the Strait of Hormuz. The first part of the decline, between 2 p.m. and 3 p.m., came before that report and has no identified trigger.
Later in the evening, an Israeli television report claimed U.S. forces had struck an anti-ship missile launcher at Sirik. No U.S. military or government confirmation followed, and the origin of the explosions remained unexplained. If such a strike were confirmed, it would appear to meet the contracts' definition of a qualifying action, which is why the claim matters so much to these prices.
The overnight recovery
By 5:33 a.m. Thursday, the contracts had recovered part of the loss: Oct. 24 was at 88.5 cents, Oct. 31 at 73.5, Nov. 8 at 59.5, Nov. 15 at 51 and Nov. 30 at 38.5.
The recovery was uneven. The Oct. 24 contract regained about three-quarters of its drop. The others regained between a third and about half: 45% for Oct. 31, 40% for Nov. 8, 53% for Nov. 15 and 33% for Nov. 30. Traders appear to have largely discounted an imminent U.S. strike while keeping more risk priced beyond this week.
That fits the evening's other news. A report citing unnamed U.S. officials said American and Israeli planners had drawn up options for strikes on Iran after the Nov. 3 midterm elections, though President Trump had not approved any plan. The November contracts did not fall further after that report, but they also did not recover as much as the Oct. 24 contract.
A disconnect with oil
Brent crude rose about 3% overnight to $112.18 a barrel, even as the near-dated ceasefire contracts recovered. The two are pricing different things. Oil's rise came alongside a drone attack on a Saudi oil field and a U.S. drawdown of staff from Saudi Arabia, events that do not affect these contracts at all.
What to watch
Any U.S. or Iranian official account of the Sirik explosions; the Oct. 24 expiry; and whether the gap between the late-October and November contracts widens as the midterms approach. Liquidity across the event was about $930,000 earlier in the week, enough for prices to be meaningful but small next to the oil market.