U.S. and Iranian forces exchanged heavy fire overnight across the Strait of Hormuz, shattering a month-old ceasefire and threatening the chokepoint that carries roughly 20% of global oil supply. American warplanes struck Iranian military sites after the Islamic Revolutionary Guard Corps fired on a containership transiting the strait, while Tehran claimed retaliatory hits on U.S. bases in neighboring states. President Trump formally declared the truce dead last week, citing repeated Iranian attacks on commercial vessels.

Oil markets reacted immediately, with Brent crude jumping above $85 a barrel on supply-disruption fears. Tanker war-risk premiums surged, and major insurers began reviewing coverage for transits through the strait. Shipping lines including Maersk and MSC rerouted vessels around the Cape of Good Hope, adding 10-14 days and $500,000-$1 million per voyage in fuel and charter costs.

The escalation complicates nuclear talks and raises the stakes for Gulf producers. Saudi Arabia and the UAE face pressure to boost output if flows are curtailed, but spare capacity remains tight. Any sustained closure would rip through global energy markets, inflation data, and central-bank policy calculus.