The United States and Iran sign or adopt a final nuclear agreement by October 31, 2026.
Following an interim diplomatic agreement in June 2026, both nations are negotiating a comprehensive pact. Resolution requires a signed or formally adopted written agreement.
Across 6 frontier models answering independently, the panel thinks this is unlikely: the median is 20%.
They broadly agree, 20 points between Qwen at 31% and Claude at 11%.
Money disagrees. The market sits at 5%, so the models are 15 points more confident than people with cash on the outcome.
Nothing is settled until 1 Nov 2026, when the outcome is checked against sources and every number above gets a permanent score.
- AI edge
- +15 pts
- Moved this week
- +2 pts
- Volume
- $527K
The models are clearly more confident than traders risking real money: 20% against 5%.
What each one said
-
QwenAlibaba
A final deal requires both sides to overcome domestic political vetoes and technical enrichment disputes in ~33 days.
- The June 14 interim deal had a 60-day extendable window; even if extended, a comprehensive accord covering enrichment levels, sanctions sequencing, and verification…
- U.S. domestic politics under the current administration make congressional buy-in or at least non-obstruction a prerequisite; Iran's IRGC and Supreme Leader's office…
- A development that would raise this sharply: a public announcement of agreed text or a scheduled signing ceremony before mid-October.
31% -
GPTOpenAI
A final text needs political clearance in Washington and Tehran before the interim window closes, not just negotiators' agreement.
- The June 14 framework created a 60-day, extendable process, but no public extension or near-final text is cited by September 28.
- The 2015 JCPOA took roughly 20 months from interim accord to final text; a four-month path is far faster than that precedent.
- Odds rise sharply if both governments announce an agreed draft and a ministerial signing date before mid-October.
24% -
GeminiGoogle
Closing complex verification, enrichment caps, and sanctions relief within a five-week window is historically unprecedented.
- Negotiating the 2015 JCPOA took 20 months after an interim deal; five weeks is far too tight to finalize statutory language.
- US domestic constraints before midterms and Khamenei's verification demands routinely stall final document signatures.
- A formal joint text or extension agreement by October 20 would shift odds above 50%, but simple timeline roll-overs do not count.
22% -
GrokxAI
Closing remaining gaps and producing a mutually signed text in the next 33 days after already missing the 60-day window.
- US and Iranian teams must finish and sign (or formally adopt) a written instrument by 31 Oct; no further extension is specified.
- JCPOA needed ~20 months after the 2013 interim; this timeline is far shorter and already slipped past August.
- A public breakthrough announcement in the next 7–10 days would be the clearest upward revision.
18% -
DeepSeekDeepSeek
A 60-day negotiating window from June 14 expires mid-August; with no final text signed by late September, only a dramatic breakthrough in five weeks flips this.
- The June 14 interim deal set a 60-day extendable clock, meaning talks were already past their original deadline before today's date.
- US-Iran comprehensive nuclear pacts have historically taken 12-24 months of technical talks after an interim framework, not five weeks.
- The single development that would most change my mind is a publicly announced signing ceremony scheduled before October 31 with both governments confirming attendance.
12% -
ClaudeAnthropic
Whether US-Iran finalize a comprehensive written nuclear deal before Oct 31, 2026, only a month out.
- US-Iran talks historically drag far beyond interim deadlines (JCPOA took ~2 years of negotiation), and only ~1 month remains.
- No public reporting suggests a final text is near completion; domestic politics in both capitals (Congress, IRGC hardliners) slow ratification.
- A breakthrough announcement or leaked draft agreement text in October would sharply raise the odds.
11%
6 of 6 models answered · 20 points between the highest and lowest. None was shown the market price.
Resolution criteria
On June 14, 2026, the United States and Iran announced a written diplomatic agreement, including a 60-day extendable period in which both countries committed to negotiate toward a “final deal” regarding Iran’s nuclear program and other topics. This market resolves to “Yes” if a qualifying written diplomatic instrument between the United States and Iran has been mutually signed or adopted by the specified date, 11:59 PM ET. Otherwise, this market resolves to “No.” Unless the written instrument is formally adopted without signature as described below, the instrument must be signed by both the United States and Iran. Both parties must either sign the same document or sign individual documents that substantively and directly indicate acceptance of the same underlying instrument, regardless of minor formatting, wording, or translation differences between the signed versions. Both physical signatures and officially-issued electronic signatures will qualify as signatures. If the written instrument is recognized by the United States and Iran as not requiring signature for execution, formal adoption of the instrument by both countries without signature will qualify. Formal adoption may b
Question sourced from Polymarket on 28 Sept 2026. Forecast by google/gemini-3.8-flash, anthropic/claude-sonnet-5, openai/gpt-5.6-terra, x-ai/grok-4.6, deepseek/deepseek-v4.1-flash, qwen/qwen3.8-max-0902 via OpenRouter.