US-Iran Ceasefire Collapse Odds on Polymarket: July 29, 2026

Less than a week after the U.S. paused its bombing campaign on Iran, Iran broke the calm first. On July 28 the Islamic Revolutionary Guard Corps (IRGC) launched an "attempted surprise attack" with ballistic missiles at a U.S. base in Jordan; U.S. Central Command said all of them were intercepted. The U.S. and Saudi Arabia struck back at Iran-backed militia sites across Iraq within hours. Polymarket's dated markets on whether the U.S. and Iran reach an effective ceasefire - the same ladder covered here two days ago, when the pause was holding and every rung was pricing higher - fell 8.5 to 18.5 cents overnight. Numbers below are from the Gamma and CLOB APIs, fetched 2026-07-29 09:20 UTC.

Every cutoff date priced lower than yesterday

"US x Iran Effective Ceasefire by...? (2-week pause)" is the same event split into four dated Yes/No markets covered here on July 27: will there be a continuous 14-day stretch with no U.S. strike on Iran, where the most recent strike falls on or before that cutoff date? Every rung fell today - a mirror image of the climb covered two days ago.

EFFECTIVE CEASEFIRE (2-WEEK PAUSE)   PRICE    24H
By Jul 24                            35.85c  -18.45c
By Jul 31                            41.00c  -13.50c
By Aug 14                            51.50c  -12.50c
By Aug 31                            62.00c   -8.50c

The event has traded $1.13M in the last 24 hours against $289K of resting liquidity - roughly double the volume from two days ago, on a ladder now moving in the opposite direction.

Thirteen nights of strikes, then an attack from the other side

Through Monday the pause looked like it might hold: the U.S. had not struck Iran since July 23, and the by-July-31 and by-August-14 contracts were climbing a fourth straight day. Then, per Al Jazeera, the IRGC ramped up drone strikes in the 72 hours before July 28 - more than 30 of them directed at U.S. and partner forces in the region. At 5:45pm ET (21:45 UTC) on Tuesday, CENTCOM said IRGC forces launched multiple ballistic missiles - no more than four, by initial estimates - at a U.S. base in Jordan in an "attempted surprise attack." All were intercepted; no U.S. casualties were reported. The attack landed a few hours after President Trump and Israeli Prime Minister Netanyahu wrapped a 90-minute White House meeting the two governments called "positive and productive." A couple of hours after that, U.S. and Saudi Arabian aircraft struck Iran-backed militia sites across seven Iraqi provinces - the first confirmed Saudi participation in strikes since the war reignited in February - killing at least 20 fighters and wounding 32, per wire reports. CENTCOM added that "the IRGC and its terrorist proxies must cease these attacks to avoid further U.S. military response." Oil moved with it: Brent crude was up 3.9% to $87.30 a barrel and WTI up 3.8% to $82.30 as of 4:30am ET, tracking renewed fear over Strait of Hormuz shipping.

A 28-point drop in under an hour, then a partial bounce

The by-July-31 line shows the shock in one move. It spent Tuesday morning grinding higher - 55c near midday - before peaking at 62.5c around 5:00-5:30pm ET, right as the missiles were in the air, then fell to 44.5c within fifteen minutes of the attack and bottomed at 34.5c by 6:30pm ET. It partly recovered overnight, touching 48.5c around 9:30pm ET, before drifting back down to the 41c it prints now: down 21.5 points from Tuesday's peak, but up 6.5 points from Tuesday's low.

Iraq isn't Iran, but the market didn't split hairs

It looks strange that a strike on Iran-backed forces in Iraq, not on Iranian soil, moved a market defined around "no U.S. strike on Iran." These contracts pay out on a continuous run, and Wednesday's retaliation - whatever it technically counts as - reads to the market as the same conflict reigniting, not a contained, separate episode. Compare the "Israel x Iran ceasefire continues through...?" ladder, which tracks whether either of those two countries fires on the other: its July 31 rung is still at 90.5c, down only 5.5 points, and the near-dated contracts haven't moved off effectively-certain at all. That front has stayed quiet since April; this week's escalation is specifically the U.S.-Iran track, and the price action shows traders treating the two as genuinely separate risks rather than one blended Middle East number.

Tight at the touch, contested on both sides

The by-July-31 book shows a 40c bid against a 42c ask right now - a tight two-cent market with real size on both sides, about 1,860 shares on the bid and 3,200 on the ask at the touch. That's a different shape from a market in one-sided panic: after a 28-point crash and a partial bounce, buyers and sellers are actively contesting the same price rather than one side pulling every quote, which reads as genuine two-way uncertainty about whether this episode ends here or escalates further.

Four dates, one screen

A dated ladder that can move 28 points in under an hour is awkward to track one market at a time. In polymarket-tui, opening the event lists every date's price and 24-hour move in one table, and drilling into any one shows its live order book and price history inline. No account is needed to browse.

$ uv tool install polymarket-tui
$ polymarket-tui

The install page has Homebrew and one-liner options.