As one fifth of the world’s oil supply remains trapped behind the Strait of Hormuz, oil prices have surged past $100 per barrel. Saudi Arabia diverting only a fraction of its oil via the Red Sea port of Yanbu, leaving 15 million barrels per day (bpd) stuck in the Middle East. The United Arab Emirates is also struggling to divert some of its crude oil exports through the Fujairah oil terminal.

This is the biggest oil shock the world has attempted to absorb since World War II, and President Donald Trump is running out of options to keep prices down.

Iran’s new supreme leader, Mojtaba Khamenei, has ordered the waterway to remain closed but has offered coordination with Iran’s navy for ships to pass through. The United States, meanwhile, has been unable to force passage through the strait.

Trump has offered to insure vessels for war-related damages and called on other countries to militarily escort ships using their navies.

About 12 million bpd of oil remain trapped behind the Strait of Hormuz. The International Energy Agency agreed to release 400 million barrels of oil from strategic reserves. The U.S. offered to contribute 172 barrels and lifted sanctions on Russian oil.

However, all the options to lower prices, including cutting taxes, will likely have little impact on crude oil prices.