Iran Attacks Slow Oil Tanker Traffic Through Strait of Hormuz

Oil tanker traffic through the Strait of Hormuz has slowed after Iranian attacks on three commercial ships this week pushed the Persian Gulf to the brink of a renewed war.

Thirteen tankers crossed Hormuz on Wednesday compared with an average of 33 per day over the previous week, said Matt Smith, director of commodity research at the trade intelligence firm Kpler. The ships either followed the route controlled by Iran or switched their transponders off to avoid tracking, Smith said.

Oil prices have rallied more than 6% this week as investors worry that crude exports through Hormuz could plunge again as the U.S. and Iran fight for control of the strategic sea lane.

President Donald Trump said Wednesday that he believed the ceasefire with Iran was over after Tehran attacked three tankers transiting Hormuz earlier this week. The U.S. has launched two rounds of airstrikes against Iran and reimposed oil sanctions in retaliation for the tanker attacks.

"The collapse of the ceasefire framework, the reimposition of Iranian oil sanctions, and the scale of U.S. kinetic action inside Iran represent the most significant escalation of the conflict since its opening phase," the maritime intelligence firm Windward told clients in a Wednesday note.

But the oil market is not pricing in a complete closure of the strait, said Andy Lipow, president of Lipow Oil Associates, in a note to clients Thursday.

"It appears to be pricing in a new normal where periods of conflict (perhaps we might call them missile skirmishes) occur between periods of relative calm (or unease) that permit the transit of tankers," Lipow said.

Oil exports through Hormuz had rebounded after the U.S. and Iran signed a memorandum of understanding on June 17 to reopen the strait. Tehran promised safe passage to ships and agreed to not charge a toll for 60 days under the interim deal with the U.S.

But Tehran has demanded that ships use a northern route under its control to enjoy safe passage. It has attacked vessels using a southern route along Oman's coast that is protected by the U.S. Navy.

"This is part of this sporadic targeted campaign by Iran to destabilize that southern corridor and send a message to Gulf State producers that are not sending their oil via that northern corridor," said Michelle Wiese Bockmann, a senior maritime intelligence analyst at Windward.

Iran basically shut down Hormuz by threatening commercial ships after the U.S. and Israel launched a massive wave of airstrikes on Feb. 28 that killed its head of state Ayatollah Ali Khamenei. The closure of the strait dragged on for months, triggering the biggest supply disruption in history.