The United States and Iran entered a seventh consecutive day of open hostilities on July 18, 2026, with US strikes hitting Iranian targets further north and a naval blockade choking off the Strait of Hormuz, sending crude oil prices up 13% in a week and toward the $100-a-barrel threshold. The New York Times

The immediate trigger for the current escalation was an Iranian attack that killed two Americans, which prompted the US to launch strikes against Iran. The New York Times The week-long exchange of fire has largely unraveled a truce that had held during the previous month. Reuters

The military campaign, designated Operation Epic Fury, originally launched at 1:15 a.m. EST under Defense Secretary Pete Hegseth's direction, targeting the Islamic Revolutionary Guard Corps (IRGC), the branch of Iran's military tasked with protecting the country's Islamic political system. Defense.gov Hegseth described the operation's goals as "laser-focused." After an initial phase and a temporary truce, the US resumed military strikes against Iran on Monday, July 13. WWLP-22News Al Jazeera reported that the US bombed Iranian cities in that wave, with the Hormuz standoff intensifying. Al Jazeera

Iran responded by escalating attacks on US bases in Gulf states and warned of further incidents in the strait. Reuters Tankers transiting the Strait of Hormuz came under attack the same day. Reuters

On the naval front, the US reimposed a blockade on Iranian ports, effective early Wednesday, July 15, over Tehran's attacks on shipping. AP News President Donald Trump stated the naval blockade of the Strait of Hormuz would be reinstated following a weekend of reciprocal strikes. MarketWatch The same day, the US disabled an Iranian ship. AP News

The strike campaign broadened geographically. AP News reported on July 15 that the US intensified strikes targeting Iran, hitting targets further north than in previous days. AP News Reuters, citing US officials, reported that strikes targeted Iranian air defenses, coastal radar sites, and other military infrastructure, strengthening Trump's options for further escalation. Reuters

By Thursday, July 16, the two sides were exchanging intensifying fire, with Reuters reporting that Iran warned the Strait of Hormuz was a "red line" and that Tehran would "resist until the end." Reuters A separate dispute over the release of an American held by Iran remained unresolved. Reuters ILTV News reported on July 19 that the conflict had entered a "dangerous new phase," with a stalemate over the Strait of Hormuz. ILTV News

A diplomatic thread has also surfaced: CNN reported on July 18 that the US and Iran had reached an agreement to end fighting in Lebanon, though the broader confrontation continued unabated. CNN

The Oil Market Response

The oil market has absorbed the escalation in a sustained, one-directional move. Crude prices settled nearly 5% higher on July 7 after Trump threatened fresh strikes. Reuters Brent crude, the global benchmark for oil prices, rose above $76 a barrel on July 8 for the first time in two weeks. Al Jazeera As the mutual strikes ramped, oil prices climbed 13% over a single week, with MarketWatch reporting prices could head above $100 a barrel. MarketWatch US oil prices had previously been holding above $110 a barrel earlier in the conflict cycle before easing. MarketWatch

The supply backdrop gives the blockade outsized leverage. Persian Gulf oil exports reached roughly 16 million barrels a day in June 2026, an increase of 6.5 million barrels a day that had been helping bring prices down. The New York Times That volume now transits a chokepoint under active US blockade and Iranian retaliation.

What It Means for Markets and Households

The broader context here is that a blockade on the Strait of Hormuz, through which roughly a fifth of global seaborne oil flows, injects a structural supply risk that no demand-side softening can offset. Think of it as a toll booth on the world's busiest oil highway: when the booth is open, supply flows freely and prices stay calm; when it shuts, every barrel that would have passed through becomes a question mark. For consumers, the pass-through is gasoline and diesel prices at the pump. For institutional investors, the question is whether the current 13% weekly surge is a geopolitical premium, meaning the extra amount traders pay because of war risk, that unwinds with the next truce or the beginning of a sustained supply shock. The answer depends entirely on how long the Hormuz blockade remains in force and whether Iran follows through on its threat to treat the strait as a red line. Both sides have signaled escalation, not de-escalation, and the Lebanon agreement reported by CNN does not extend to the maritime theater where the oil supply chain sits.

Reuters reported that US officials characterized the strikes as expanding the president's escalation options, not narrowing them. That framing, combined with the geographic broadening of strike targets further north into Iran, suggests the campaign is in an expansion phase rather than approaching a negotiated off-ramp. The unresolved American detainee dispute adds another friction point that could delay any diplomatic resolution.

In my view, the key variables to monitor are tanker traffic data through Hormuz, any change in the blockade's enforcement perimeter, and the trajectory of Brent relative to the $100 threshold cited by MarketWatch. Each additional day of blockade compounds the inventory draw at the refiners most exposed to Gulf crude, and the longer the conflict persists, the more likely the geopolitical premium becomes embedded in the term structure, meaning the pricing of oil contracts over future months, rather than remaining a spot-market reaction, meaning a reaction to today's price only.