US-Iran nuclear deal by June 30?

Platform comparison

Market context

A publicly announced US-Iran nuclear agreement by 30 June would be a rare, deadline-driven diplomatic outcome rather than a broad peace settlement. The current 30% Polymarket price suggests the crowd sees some chance of a late-stage accord, but not a likely one. That reading is consistent with the last major benchmark: the 2015 JCPOA showed that nuclear deals can emerge only after prolonged bargaining and then move quickly once the terms are locked. Since Washington left that agreement in 2018, and many of its provisions expired in October 2025, the present talks have been starting from a weaker baseline, with both sides openly disputing core issues such as enrichment, inspections and sanctions relief.

For comparison across venues, Polymarket shows the event as an implied probability, while Betfair and Smarkets would usually be priced in decimal odds and Kalshi in contract terms, so the same view can look different once fees and spreads are included. That matters here because a 30% probability on Polymarket is roughly equivalent to 3.33 decimal odds before costs, but the realised entry price on exchange-style books depends on liquidity, commission and whether the market is being backed or laid. KYC access also differs: Kalshi is US-regulated and more constrained by jurisdiction, whereas Polymarket and offshore exchange books may be accessible to a broader set of users depending on location.

The main catalysts are the next negotiating round, any White House or Iranian foreign ministry statement, and whether the parties soften their maximalist positions on enrichment and sanctions. Reuters reported on 2 June that Iran was preparing to reject the US proposal, while earlier reporting said the fifth round of talks in Rome ended without a breakthrough. Traders should also watch for signs that Iran will accept temporary enrichment limits, IAEA access, or a freeze on stockpiles, since those are the sorts of details that can turn a framework into a publicly announced deal before the deadline.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares US-Iran nuclear deal by June 30? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. Live odds come from the Polymarket order book; the other venues' contract details are maintained manually because their APIs aren't directly comparable. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Where can I trade this market with the lowest fees?

On PolyGram, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does it cost to trade on PolyGram?

Zero. PolyGram routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.