US-Iran Final Nuclear Deal by…?

Platform comparison

Market context

The key real-world event is the June 2026 written US-Iran framework, which was reported as a roadmap to a fuller nuclear settlement, not a completed final deal. Reuters said the parties were close to a signing and that a 60-day negotiation period would follow, while later reporting from AP described an initial pact that set the timetable but still left the core nuclear terms to be negotiated[9][15].

That distinction matters for pricing because this market resolves only if a qualifying written diplomatic instrument is mutually signed or formally adopted by 31 August 2026. In previous rounds this year, reporters repeatedly noted “progress” and “guiding principles” without a binding end-state, so traders have to separate a preliminary MoU from a final instrument[3][4][5]. On Polymarket, that usually shows up as a straight implied probability; on Kalshi it is tied to contract price in cents; on Betfair and Smarkets you instead read the market through decimal odds, with exchange commission making the effective entry price slightly worse than the headline quote. KYC access also differs: Kalshi is US-regulated, while Betfair and Smarkets are UK-facing exchanges with broader European-style verification.

The main catalysts are the next diplomatic milestone, any published text of the instrument, and whether technical talks actually convert the June roadmap into a signed document before the deadline. Reuters reported that a signing ceremony in Europe was under discussion and that the deal would be followed by the 60-day period, so any cancellation, delay, or change in venue would matter immediately[9]. If no final signed text emerges, the market can stay anchored near the crowd’s 0% YES until the final days, because this is a binary settlement on paperwork, not on rhetoric or partial progress.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares US-Iran Final Nuclear Deal by…? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Alternative UK, 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.

UK Frequently Asked Questions

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

Polymarket vs Betfair Exchange: which is better for UK prediction trading?

Betfair Exchange offers UKGC regulation, GBP settlement, and potentially tax-free winnings — but focuses on sports and politics only. Polymarket has deeper liquidity, 0% platform fee, global event coverage, and crypto/geopolitical markets Betfair doesn't offer. For UK traders: Betfair for regulated GBP sports markets; Polymarket for broader, global prediction events.

Is Kalshi available in the UK?

Kalshi is a US CFTC-regulated prediction exchange. UK residents can create accounts but must use USD and US payment methods. Kalshi's product range overlaps with Polymarket but with lower liquidity on most contracts. For UK traders, Polymarket typically offers better prices due to higher global volume.