Oil prices jumped sharply on July 7 after Iran fired missiles at commercial ships in the Strait of Hormuz, hitting at least three tankers including a Qatari vessel and a Saudi oil tanker Reuters. Within a day, at least four oil and gas ships turned back rather than attempt the passage Reuters. This reversed a sudden price drop from just the day before CNBC.

The shift happened fast. On July 6, oil prices were falling because supply was expected to improve. OPEC — the organization of major oil-producing nations — had pledged to pump more oil, and a US-Iran ceasefire agreement from July 1 had raised hopes the strait would reopen for normal shipping NYT; AP. Within a week, military action had undone that agreement.

The US responded by tightening its grip on Iranian oil exports. It canceled permission for Iranian crude sales, put sanctions back in place, and launched military strikes on Iranian targets Reuters. Iran's military command had warned on July 2 that ships must use approved shipping lanes or face attack — a warning that became reality days later AP. Iran said it would not negotiate unless the US stopped military strikes Reuters.

Why does this matter? About one-fifth of the world's oil shipped by sea passes through the Strait of Hormuz. When ships cannot safely transit, oil becomes scarcer, pushing prices up. The World Bank had estimated that earlier supply disruptions left the market short by 3.7 million barrels a day in the second quarter of 2026 — showing how tight supplies were even before this week's attacks World Bank.

Shipping insurance has been getting more expensive. Lloyd's, the world's largest insurance marketplace, created a special insurance program on June 19 for ships crossing the strait Lloyd's. With the strait now flagged as a severe risk zone Reuters, the cost to insure a tanker has jumped sharply — and these insurance costs add directly to the price consumers and businesses pay for oil.

Here is something traders often miss. Even if diplomats reach a new deal tomorrow, getting oil to flow normally again takes weeks or months. Ships must find new routes, get insurance clearance, and crews must verify safety — processes that cannot be rushed AP. Because of this lag, oil should stay scarce and expensive well after any good-news headline appears.

The market swung violently in one week — prices down on July 6 expecting supply relief, then sharply up on July 7 when attacks hit. Such swings make it harder for traders and companies to hedge their risk, and insurance costs are now moving faster than the oil price itself. Traders should watch real-time ship location data from ships' GPS systems as carefully as they watch the news; four ships turning back is an early warning sign that disruptions are coming, whether or not a government says so.

One more layer: the US has blocked most Iranian oil sales through sanctions. As Gulf oil supplies tighten from attacks, buyers are forced to switch to oil from other Gulf producers — the same producers whose ships face the same dangerous passage.