US strikes Iran after tanker attack, threatening 21% of oil supply

The US military struck Iranian targets on June 26 in retaliation for an attack on a merchant ship in the Strait of Hormuz, a waterway that handles about 21% of global oil consumption, the US Central Command said.

"The US military conducted strikes against Iran in response to the attack on a merchant vessel transiting the Strait of Hormuz," the US Central Command said in a social media statement.

The escalation follows a projectile strike on a container ship near the coast of Oman on June 25, which a US official attributed to Iran. The incident highlights the fragility of the US-Iran understanding as tensions over the broader regional conflict persist. The targeted vessel was struck while transiting international waters, according to the US official, though the extent of damage and any casualties have not yet been disclosed.

The Strait of Hormuz is the world's most critical energy artery, with roughly 21 million barrels of oil passing through daily, according to the US Energy Information Administration. Any sustained disruption risks a supply shock that could push crude prices sharply higher, reignite inflation pressures and force central banks to reassess rate paths. The waterway connects Persian Gulf producers including Saudi Arabia, Iraq, the UAE and Kuwait to global markets, making it indispensable for Asian refiners who rely on Middle Eastern crude. Japan, South Korea, India and China are among the largest importers of oil that transits the strait.

The attack on the merchant vessel was the latest in a series of maritime incidents that have raised the risk premium on oil shipments through the region. The US-Israeli war with Iran has already reshaped trade flows across the Middle East, and Thursday's US military response marks a significant escalation in direct American involvement. Shipping companies may now face higher insurance premiums for transiting the region, adding to supply chain costs that could be passed on to consumers.

President Donald Trump said the Strait of Hormuz remained open and called Iran an opportunity for domestic farmers, according to a statement. The comment came as some market participants assessed the risk of a broader supply disruption. US agricultural exporters could benefit if Iranian imports are disrupted, though the primary market concern remains energy supply. The administration's stance suggests it views the escalation as containable, though military analysts caution that the situation remains fluid.

The US military action comes against the backdrop of an ongoing US-Israeli war with Iran that has already reshaped the Middle East's strategic landscape. The conflict has drawn in regional proxies and raised the risk of a broader conflagration that could disrupt energy infrastructure across the Persian Gulf. Iran has previously threatened to close the Strait of Hormuz in response to military pressure, a threat that now carries greater weight given the direct US strikes.

Market Impact

The geopolitical risk premium embedded in crude oil options is likely to widen sharply. Defense sector stocks may see a bid as investors price in prolonged military engagement. Safe-haven assets including gold and the US dollar are expected to attract flows, while equity markets face headwinds from higher energy costs and uncertainty. The VIX, Wall Street's fear gauge, is likely to rise as traders hedge against further escalation. Bond markets may also react, with longer-dated Treasury yields potentially falling on flight-to-safety flows while short-term yields adjust to inflation expectations.

The last time the US launched direct strikes on Iranian-linked targets, crude prices surged and equity markets sold off as the conflict premium repriced across asset classes. Following the US strike that killed Qassem Soleimani in January 2020, Brent crude rose above $70 a barrel and the S&P 500 fell over the following week before stabilizing, according to historical market data. The current escalation comes with oil prices already elevated by the broader regional conflict, raising the stakes for global markets.

For investors, the key variable is whether the strikes remain a limited retaliatory action or expand into a broader military campaign that disrupts tanker traffic through the Strait of Hormuz. A sustained blockade could remove as much as 21 million barrels per day from global supply, a scenario that would dwarf the 1973 oil embargo in scale. The next 48 hours will be critical in determining the trajectory of the conflict and its impact on global markets. Traders will watch for any signs of Iranian retaliation, statements from OPEC members on supply adjustments, and the path of crude futures when markets open.

This article is for informational purposes only and does not constitute investment advice.