According to CryptoComLearn, the Polymarket prediction contract on the normalization of traffic through the Strait of Hormuz experienced a dramatic reversal on April 18, 2026. Iranian Revolutionary Guard Corps gunboats reportedly fired on at least one oil tanker and forced more than 20 vessels attempting transit to turn back, causing the odds of the waterway returning to normal by April 30 to collapse. The 'Yes' probability on the April 30 contract dropped 41% from its recent peak, settling at just 28%.
Iran Reverses Course Within 24 Hours
Just one day earlier, Iran's foreign minister had declared the strait 'completely open' to commercial shipping, citing a Pakistan-brokered ceasefire. Global oil prices fell roughly 10% on the news, equity markets rallied, and the May normalization contract on Polymarket briefly touched intraday highs near 82%. However, within hours, Iranian officials accused the United States of maintaining a naval blockade on Iranian ports, calling it a 'breach of trust' and a violation of ceasefire terms. Military forces swiftly reimposed restrictions, and gunboats began actively interdicting vessels.
Data from IMF Portwatch shows daily vessel transits currently range between 5 and 16 ships, far below the pre-crisis average of over 60 ships per day. Even if commercial traffic resumed immediately and fully, reaching a 7-day moving average of 60 vessels within the remaining 12-day window would be mathematically improbable. The April 30 contract has accumulated over $16 million in total volume, with nearly $4 million changing hands during a single session on April 7 after an earlier Iranian pledge to reopen the waterway.
May and June Contracts Reflect Different Time Horizons
As of April 18, the Polymarket May normalization contract held at 69% Yes, backed by $1.3 million in volume. The June contract remains elevated at around 81% Yes, suggesting traders see longer-term resolution as more probable but near-term stabilization as highly uncertain. MarineTraffic recorded multiple vessels executing U-turns near Larak Island after Iranian enforcement resumed, while Kpler data indicated 8 tankers had managed to transit early Saturday before the crackdown began.
The Strait of Hormuz carries roughly one-fifth of global seaborne oil and substantial volumes of liquefied natural gas. Since Iran effectively declared the strait closed around March 4, 2026, following U.S. and Israeli military operations, at least 10 vessel attack incidents have been reported. The White House maintained its position on April 18, stating that the U.S. blockade would remain until a comprehensive deal with Iran is concluded.
Analyst Perspective: Mathematical Hurdle Outweighs Political Drama
For the April 30 contract, the challenge extends beyond geopolitics. The 7-day moving average has hovered near zero for weeks. Even with an immediate, full resumption, hitting a 60-vessel average in just 12 days is a formidable barrier, which explains why 72% of capital is now betting 'No.' Insurance premiums for vessels attempting Hormuz transit remain sharply elevated, and shipping firms have broadly suspended sailings pending clearer security guarantees.
Pakistan continues to mediate between Washington and Tehran, but no formal talks are currently scheduled, and no timeline for a broader deal on Iran's nuclear program has been announced. 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 market has placed its bet heavily on continued disruption.