US-Iran Conflict Reignites: Why and Market Reaction

Original | Odaily News (@OdailyChina)

Author | jk

In the US-Iran conflict that has lasted nearly half a year, a military operation on August 30 local time broke a month-long relative calm. The war, which began in February, had entered an intermittent phase due to diplomatic mediation and economic sanctions strategies. But this weekend, the two sides exchanged fire again, Brent crude immediately broke above $90, and the three major US stock indices fell collectively, putting the market on edge once more.

Why the Conflict Reignited

Direct Trigger: Naval Mine-Laying Attempt in the Strait of Hormuz

On August 30 (Sunday), US Central Command confirmed that US forces struck rocket launchers deployed by Iran on Larak Island. Central Command spokesman Tim Hawkins said that the Islamic Revolutionary Guard Corps (IRGC) was preparing to lay mines in the Strait of Hormuz. This was the first time the US publicly acknowledged military action against Iranian targets since late July.

Iran responded quickly: Iranian state media said Tehran had launched missiles at US military bases in Jordan as retaliation, and the two bases were reportedly "severely damaged." The IRGC subsequently claimed that an oil tanker attempting to pass through the southern edge of the strait was hit by two mines.

Background: From "Military Confrontation" to "Economic Choking"

This exchange of fire drew attention because it broke Washington's previous strategic shift. Since the last round of missile exchanges in late July, the US had been signaling that it would shift its focus from direct military strikes to economic sanctions and blockades against Iran—tightening sanctions and maintaining a naval blockade to pressure Tehran into returning to the negotiating table, rather than launching new airstrikes. Trump had previously said the US would "just watch Iran sink into inflation and be penniless" rather than rush to expand the war.

Meanwhile, Iran and Oman had reached a framework agreement on sharing transit fees for the Strait of Hormuz, and the market had interpreted the situation as an economic stalemate, which was why Brent crude had fallen more than 5% over the past week.

Trump's "AI Video" Interlude

On August 31, Trump posted a video on Truth Social that appeared to be AI-generated, claiming that Kharg Island, Iran's key crude oil export hub (handling about 90% of Iran's crude exports), had been "blown to pieces." But executives from the National Iranian Oil Company publicly called the claim "ridiculous," saying operations on Kharg Island were normal; US Central Command also did not confirm strikes on the island, only confirming "limited, precision strikes" against the mining operation on Larak Island.

Source: Truth Social

Although this interlude did not cause a new substantive military escalation, it further stirred market expectations about the direction of the situation. Trump had previously threatened publicly multiple times to "take over" Kharg Island and Iran's oil and gas market, comparing it to US actions in Venezuela.

In early September, the originally scheduled framework negotiations were still on the agenda, but Washington and Tehran remained publicly opposed on the core issue of "who controls the weapons." In other words, even if both sides still maintain dialogue channels, the conflict has not truly cooled. The exchange of fire on August 30-31 was more like another friction under this fragile stalemate, and it is currently unclear whether Iran will retaliate further or announce that this round of responses has ended.

Market Impact

Oil Prices: Rose in Response, Breaking Above $90 Again

• Brent crude closed at about $90.69 per barrel on August 31, up 2.93% on the day; WTI crude rose in tandem, approaching $86 per barrel.
• This increase reversed the previous decline caused by "the Iran situation being seen as economic sanctions rather than a supply threat"—Brent had fallen to around $89.3 the previous week, with a cumulative weekly decline of over 5%.
• Over a longer period, Brent crude is currently up about 33% year-on-year, and up about 8% over the past month. Gulf crude production remains significantly below pre-war levels (according to Goldman Sachs estimates, current Persian Gulf exports are about 15–16 million barrels per day, compared to 22–24 million barrels per day before the war).

Brent crude suddenly rose. Source: Hyperliquid

US Stocks: Energy Stocks Strengthened, Broad Market Impact Limited

Closing on August 31 (Monday):

• Standard & Poor's 500 Index (S&P 500) fell 0.33% to 7,686.14 points
• Nasdaq Composite fell 0.12% to 26,370.89 points
• Dow Jones Industrial Average fell 374.09 points (-0.7%) to 53,185.90 points, mainly dragged down by Goldman Sachs and Alphabet

It is worth noting that despite Monday's decline, the three major indices still posted gains for the entire month of August: the S&P 500 rose 2.6% for the month, the Nasdaq rose 3.9%, and the Dow rose 1.3% (its fifth consecutive monthly gain).

Sector level: Energy stocks rose collectively on higher oil prices, with Halliburton up more than 2.5% in pre-market trading, Chevron up 2%, Valero and Occidental both up 2%, and Exxon Mobil up more than 1.5%.

Most crypto-related stocks rose, with Bitcoin holding above $78,000. Coinbase, Strategy, CleanSpark, etc. were up between 1% and 2%.