US announces blockade on Iran by 2026?

Platform comparison

Market context

The United States has already imposed a naval blockade on Iran, effective from 10 a.m. ET on 13 April 2026, following the collapse of the Islamabad Talks and the escalation of the 2026 Iran war. This real-world event means the market’s 32% “Yes” probability is not forecasting a future possibility but rather evaluating whether the official announcement will be deemed to have occurred within the settlement window, despite the blockade already being active. The announcement, issued by CENTCOM under President Trump’s direction, explicitly targeted vessels entering or departing Iranian coastal areas, including those transiting the Strait of Hormuz with Tehran’s prior approval.

Historically, similar blockades—such as the 1987 US escort operations in the Persian Gulf or the 2012–2013 sanctions-driven interdiction of Iranian oil—were framed as targeted interdictions rather than full maritime closures, yet still triggered significant market reactions. In this case, the blockade’s scope is limited to Iranian ports and coastal zones, not the chokepoint itself, aligning with CENTCOM’s legal stance that blocking international waters is unlawful. Programmatic traders should model this market as a binary event tied to the timing and wording of the CENTCOM announcement, not the physical enforcement, using conditional orders to capture the 32% implied probability if the announcement is confirmed post-13 April.

Key catalysts include the formal signing of the ceasefire agreement on 19 June, which CENTCOM stated would lift the blockade, and any subsequent US statements clarifying whether the announcement qualifies under the market’s terms. Recent reporting from Al Jazeera confirms the blockade has already cost Iran nearly $6bn in oil revenues by May, with exports plummeting from 2 million bpd to under 300,000 bpd, while USNI News notes the blockade was officially lifted on 18 June. Traders monitoring this market must watch for US Central Command updates on 19 June and any retrospective announcements that could retroactively validate the “announcement” clause within the settlement window.

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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.

FAQ

Is this market available outside the US?

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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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

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.