Who will sign U.S. x Iran deal?

Platform comparison

Market context

The United States and Iran have already signed a preliminary memorandum of understanding to end their ongoing conflict, with President Trump confirming the US side is electronically signed and awaiting in-person delegation signing this Friday. This interim accord lifts the US naval blockade, halts military operations, and opens the Strait of Hormuz, while committing both nations to a 60-day window to negotiate a final deal on nuclear restrictions and sanctions relief[1][2].

Historically, the 2015 JCPOA demonstrated that such frameworks require years of verification and face collapse when political conditions shift, as seen when Trump withdrew the US in 2018[6]. The current 3% implied probability reflects scepticism that a final, binding written agreement involving both parties as signatories will be completed before the August 2026 deadline, given the 60-day negotiation window and the central sticking point of Iran’s uranium enrichment capacity[4]. Traders should watch for the release of the full agreement details, Vance’s Geneva trip, and any progress on the $300bn reconstruction fund, which hinges on further talks[2][3].

On Polymarket, this market trades at decimal odds of roughly 33:1 against, whereas Kalshi or Betfair might express this as a 3% implied probability with different fee structures and KYC thresholds; Polymarket’s lower fees and minimal identity checks contrast with Kalshi’s strict US residency requirements, creating divergent liquidity profiles for this specific geopolitical event. The divergence in decimal odds versus implied probability representation also affects how traders assess risk across platforms, with some books offering tighter spreads on the “No” outcome due to higher regulatory compliance costs.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Who will sign U.S. x Iran deal? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

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

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.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.