US-Iran Final Nuclear Deal by…?

Platform comparison

Market context

Polymarket has this contract at **0% YES** right now, which means the market is assigning no live value to a signed US-Iran written instrument reaching the settlement standard by 31 August 2026. On Polymarket, that means buyers are holding USDC on Polygon against conditional tokens whose payout still depends on the exact wording and formal adoption of a qualifying diplomatic text, not just a political announcement.

The closest historical read-through is that US-Iran nuclear diplomacy has often produced *frameworks* and *technical roadmaps* before anything binding, while the market’s settlement rule is narrower than headlines about “progress” or “final talks”. In June, Reuters reported that a signing was possible within days and that a 60-day negotiation period would follow, while AP and Al Jazeera described an initial deal or memorandum rather than a completed final settlement[8][13][12]. That matters because this market only resolves YES if the required written instrument is actually signed or formally adopted, so interim understandings, draft texts, or public optimism do not by themselves count[8][13].

The main catalysts are the next official statements, any announced signing venue, and whether the two sides keep publishing aligned language on nuclear limits, sanctions, inspections, and implementation groups. Reuters said a ceremony in Europe was being discussed, and later reporting pointed to the 60-day follow-on talks as the real risk window for slippage or reversion[8][1]. Traders should also watch for confirmation from the White House, Iran’s foreign ministry, and mediators on whether the June instrument is being amended, extended, or replaced, because a fresh written document before the deadline would be the key settlement trigger.

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

UK Frequently Asked Questions

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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%.