What Moved the Market
The Polymarket contract on a “US x Iran permanent peace deal by May 31, 2026” declined to 13%, down 3.5 percentage points over the past 24 hours and 16 points over the past week.
The move comes late in the contract window (market ends May 31, 2026) and follows elevated trading activity, with a narrow 1.0 pp spread.
Why It Likely Moved
- Repricing appears driven by new UK measures against Iran: on May 11, the UK government announced sanctions on organisations and individuals “enabling hostile Iranian activity,” signaling hardened Western posture toward Tehran and reducing perceived odds of a near‑term peace accord UK government.
- Markets reacted to the May 12 UK decision to contribute drones, jets, and a warship to a multinational mission securing the Strait of Hormuz—an operational deployment that implies ongoing security frictions rather than movement toward a permanent cessation of hostilities UK government.
- The repricing follows continued signs of regional risk in energy: WTI crude stood at $100.97/bbl and was up 6.19% over 7 days as of May 13, consistent with a persistent risk premium rather than decisive de-escalation (source: Yahoo Finance).
- US domestic signals are mixed: on May 13, AP reported growing Senate Republican resistance to expanded US military action against Iran after Sen. Lisa Murkowski’s shift. While de‑escalatory in tone, this does not constitute progress toward a formal, permanent peace deal within the contract’s timeframe AP News.
How Strong the Move Is
The 24-hour decline (−3.5 pp) carries an extreme z-score of 12.0, indicating an outsized, statistically unusual down-move relative to recent trading. This characterizes the shift as a sharp repricing rather than routine noise.
Over seven days, the contract is down 16 pp with a “sharp” z-score (≈2.23), suggesting the move has momentum and is not merely a one-off spike. With the end date approaching, time remaining also mechanically constrains upside scenarios.
Cross-Market Confirmation
- A shorter-window analogue, “US x Iran permanent peace deal by May 15, 2026,” dropped to 1.2% (−0.3 pp 24h, −13.8 pp 7d), confirming the broader downtrend in near‑term deal odds.
- The June 30, 2026 variant fell to 34% (−1.0 pp 24h, −15.0 pp 7d), aligning directionally and indicating repricing is not confined to the May 31 deadline.
- “Iran closes its airspace by May 15?” eased to 3.3% (−0.25 pp 24h, −8.35 pp 7d). This decline in an acute‑risk indicator does not contradict the main move: reduced tail-risk can coexist with skepticism about securing a formal, permanent peace accord on the stated timeline.
News & Real-World Context
- On May 11, the UK government announced sanctions on Iranian entities and individuals tied to hostile activity, reinforcing a punitive track that is typically incompatible with imminent comprehensive peace announcements UK government.
- On May 12, the UK government said it will contribute drones, jets, and a warship to a multinational effort to secure the Strait of Hormuz, an explicit security posture around vital shipping lanes UK government.
- On May 13, French President Emmanuel Macron said France would take an initiative at the UN for a peaceful mission to secure navigation in the Strait of Hormuz—an effort focused on maritime safety rather than US–Iran political settlement Ground News.
- Also on May 13, AP reported growing Republican resistance in the US Senate to broader Iran strikes after Sen. Lisa Murkowski’s shift, signaling legislative unease with escalation but offering no concrete pathway to a signed, permanent peace deal AP News.
Bottom Line
Pricing moved sharply lower as official UK actions—new sanctions and a Hormuz security deployment—signaled continued confrontation and maritime risk management rather than progress toward a permanent US–Iran peace. With the market nearing its May 31, 2026 end date, traders appear to be discounting the feasibility of a definitive, jointly confirmed accord within the window.
Market Conditions at Time of Writing
- Current Probability: 13.0%
- 24h Change: −3.5 pp
- 7d Change: −16.0 pp
- Volume (24h): $719,727.44
- Open Interest: $953,078.12
- Spread: 1.0 pp
- Z-score (24h): 12.0
