Iran’s grip on trade is a potent weapon, but it has an expiry date

Professor in Economics of the Middle East, Philipps-Universität Marburg, Germany.

Iran has turned its ability to restrict commercial passage through the Strait of Hormuz into a potent economic weapon in the war imposed by the United States and Israel.

IMF PortWatch shows that in the seven days ending August 2, an average of only about four ships per day passed through the strait, compared with about 90 during the corresponding week of 2025. Estimated transit volume fell from 3.5 million to about 143,000 metric tonnes per day. Both indicators declined by approximately 96 percent.

This was not a temporary collapse in traffic but a sustained disruption. Since February 28, both vessel traffic and estimated tonnage have remained far below their levels in the previous year, with only brief recoveries. Tehran has therefore already demonstrated that it can impose severe disruption on commercial traffic. The question is no longer whether Iran can disrupt trade through Hormuz, but how effectively it can convert that disruption into political leverage, and for how long.

A useful framework for understanding this strategy comes from political scientists Henry Farrell and Abraham Newman, who describe how states can turn control over central nodes in international networks into coercive power, a process they call “weaponised interdependence ”. In Hormuz, the critical node is physical rather than financial or digital. Geography gives Iran leverage over a corridor on which energy producers, shipping companies and importing economies remain heavily dependent.

The scale of that dependence shows Tehran’s leverage. In 2025, almost 20 million barrels of crude oil and petroleum products crossed Hormuz each day, equivalent to about one-quarter of global seaborne oil trade. Around 80 percent of those flows went to Asia. China and India alone received 44 percent of the crude oil that passed through the strai t . Qatar and the United Arab Emirates also shipped liquefied natural gas (LNG) equivalent to almost one-fifth of global LNG trade through Hormuz, with no practical alternative export route.

The economic effects begin before any formal closure. Shipping companies and insurers respond to perceived risk as well as actual attacks. Even the threat of missiles, mines, drones or vessel seizures can increase insurance premiums, freight rates and waiting times. Research published in Nature Communications shows that disruptions at maritime chokepoints transmit economic losses through delays, rerouting, insurance costs and interruptions to production.

Iran can therefore exert pressure on several audiences at the same time. Gulf states face risks to export revenues, ports and logistics. Major Asian importers such as India face higher energy costs and possible supply shortages. The US imports comparatively little oil through the Strait of Hormuz, yet it remains exposed to higher global energy and domestic fuel prices , and the military costs of protecting commercial navigation. Tehran’s strongest leverage may therefore come indirectly by pushing Gulf governments and Asian importers to press Washington for de-escalation .