Polymarket's contract betting on normalized traffic through the Strait of Hormuz by April 30 collapsed to 28% Yes on Saturday, April 18, after Iranian Revolutionary Guard Corps gunboats fired on at least one tanker and turned back more than 20 vessels attempting transit. The sharp reversal came just one day after Iran’s foreign minister had declared the waterway “completely open,” citing a Pakistan-brokered ceasefire. Oil prices had fallen about 10% on that news, equity markets rallied, and the May normalization contract briefly touched intraday highs near 82%.
Iran Reverses Course Within 24 Hours
On April 17, Iranian officials stated that the Strait was open for commercial vessels. However, within hours, they accused the United States of violating ceasefire terms by maintaining a naval blockade on Iranian ports. By April 18, Iranian forces reimposed shipping restrictions, and the April 30 Polymarket contract dropped 41% from its recent peak. The May contract, which had spiked to 73% on April 17, settled back to approximately 69% Yes.
The April 30 market carries over $16 million in total volume, with nearly $4 million changing hands during a single session on April 7 following an earlier Iranian pledge to reopen the waterway. The “No” side now represents 72% of capital, reflecting traders’ deep pessimism about a near-term resolution.
A Mathematical Hurdle in 12 Days
Resolution for both contracts depends on IMF Portwatch reporting a 7-day moving average of at least 60 ship arrivals covering container, dry bulk, Ro-Ro, general cargo, and tanker vessels. Before the crisis began in early March 2026, daily transit calls routinely exceeded 60. Current vessel counts run between 5 and 16 ships daily. Kpler data showed 8 tankers transited early Saturday before the crackdown resumed. MarineTraffic recorded multiple vessels executing U-turns near Larak Island after Iranian enforcement resumed.
Even with an immediate, full resumption of commercial traffic, hitting a 60-vessel average within the remaining 12-day window would require a level of throughput that traders appear unwilling to price as likely. The 72% “No” side is where most capital has settled.
Geopolitical Context and Forward Outlook
The Strait of Hormuz carries roughly one-fifth of global seaborne oil and substantial LNG volumes. Iranian forces declared it effectively closed around March 4, 2026, following U.S. and Israeli military operations against Iran that began in late February. At least 10 vessel attack incidents were reported by early March. President Trump publicly welcomed the April 17 announcement but said the U.S. blockade would remain until a comprehensive deal was completed. On Saturday, the White House maintained that position.
Pakistan has been acting as an intermediary between Washington and Tehran. No formal talks are currently scheduled, and no timeline for a broader deal on Iran’s nuclear program has been announced. A companion Polymarket market on normalization by the end of June sits at approximately 81% Yes, suggesting traders see longer-term resolution as more probable than near-term stabilization. Insurance premiums for vessels attempting Hormuz transit remain sharply elevated. Shipping firms have broadly suspended sailings pending clearer security guarantees.
The April 30 contract resolves as soon as IMF Portwatch publishes qualifying data, or at the deadline if no qualifying data appears. With 12 days remaining and daily vessel counts in the single digits, the “No” side appears overwhelmingly likely to prevail.