US-Iran Final Nuclear Deal by…?

Platform comparison

Market context

The real-world event is whether the United States and Iran will produce a **written diplomatic instrument** on the nuclear issue that is mutually signed or formally adopted by the deadline. In this market, a **YES** share pays out if that qualifying document exists by 11:59 PM ET on 31 August 2026; a **NO** share pays out if it does not.

The present setup is easier to read in context of the recent June 2026 framework than in isolation. Reuters reported on 12 June that a deal was close and that a signing could happen within days, while later coverage said the two sides signed an initial pact and set a 60-day negotiation period for a final resolution.[9][15] That matters because prediction markets are not judging whether talks are “making progress”; they are pricing the specific threshold event of a signed or adopted instrument. Comparable Iran–US negotiations earlier in 2026 produced statements about “guiding principles” and “significant progress”, but not a final settlement, which is one reason these markets can stay low even when diplomacy is active.[3][4][7]

For traders, the key catalysts are formal announcements, the release of draft text, and confirmation of any signing ceremony or ministerial adoption. The market is most sensitive to whether the June framework is converted into a document that matches the settlement rules, rather than to rhetoric about talks continuing.[1][13][15] Watch for references to extension of the 60-day period, inspection access, sanctions relief, and any schedule for technical or political meetings, because those are the points that determine whether the process ends in a binding instrument or simply rolls into further negotiation.[1][2][5]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

UK Frequently Asked Questions

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.