Brent Tops $90 as IRGC Vows to Choke Hormuz and Houthis Open a Second Front

A Tenth Night of Strikes and a Warning From Tehran

The conflict between the United States and Iran entered its tenth day on Monday with no sign of de-escalation on the battlefield, even as a flicker of diplomatic oxygen kept markets from fully pricing in the worst case. US Central Command confirmed it completed its ninth consecutive night of strikes against Iran by Sunday evening, targeting military command centers, air defense systems, coastal surveillance sites, and maritime assets designed to attack commercial vessels in the Strait of Hormuz.^[1]

President Donald Trump declared on Truth Social that Iran would pay for the deaths of three American service members killed in recent fighting, including 1st Lt. Tyler James Feehan and Pvt. Isabella Gonzales, who died in an Iranian attack on Muwaffaq Salti Air Base in Jordan.^[2] A third service member was killed Saturday while disposing of unexploded ordnance from a downed Iranian suicide drone.^[1]

Iran’s Islamic Revolutionary Guard Corps responded with its most explicit threat yet against the Strait of Hormuz, vowing in a Monday statement that “not a single drop” of oil or gas would pass through the waterway as long as US “aggression” continued.^[1] The IRGC also claimed it had launched ballistic missiles at US aircraft at Jordan’s Aqaba Airport and said two tankers had exploded after attempting transit through the strait, though it provided no details about the vessels, their flags, or casualties.^[1]

Iran broadened its attacks beyond US forces over the weekend, striking a power and water desalination plant in Kuwait for the second consecutive day and triggering air-defense responses in Bahrain, home of the US Fifth Fleet.^[1]

The Chokepoint Is Nearly Closed

The shipping data tells the story more starkly than the rhetoric. Only eight vessels passed through the Strait of Hormuz on Sunday — a three-week low — down from 15 the previous week, according to shipping analytics firm Kpler. Before the US and Israel launched strikes against Iran on February 28, between 130 and 140 vessels transited the strait each day.^[1] That is a collapse of more than 94% from peacetime traffic levels. S&P Global separately reported that traffic through the strait was down 50% week-over-week,^[3] and LNG shipments through Hormuz have ground to a halt entirely.^[3]

The strait typically carries roughly one-fifth of the world’s oil and liquefied natural gas during peacetime.^[1] Its near-closure removes the primary artery for Gulf crude and LNG exports to global markets.

Brent crude, the international benchmark, closed at $89.22 per barrel on Monday, up about 1.3% on the day, after briefly trading as high as $91.01 earlier in the session.^[2] West Texas Intermediate settled at $83.23, up 0.9%.^[2] Prices have surged roughly 20% this month^[2] as the June 17 interim agreement that had briefly reopened the strait collapsed and fighting resumed on July 7.^[1] Brent nearly reached $115 a barrel in early May amid fears of prolonged disruption before retreating after an April truce.^[1]

Houthis Open a Second Front

The most significant development on Monday was not in the Gulf but in the Red Sea. Houthi militants in Yemen declared a maritime embargo against Saudi Arabia, effective immediately, threatening to close the Bab el-Mandeb Strait — the narrow chokepoint connecting the Red Sea to the Gulf of Aden and global shipping lanes.^[4] A Houthi military spokesperson, Yahya Saree, announced the blockade in a video statement, framing it as retaliation for a Saudi attack on Sanaa International Airport.^[4]

This is the development to watch most carefully. Saudi Arabia has been diverting millions of barrels of oil per day through an internal pipeline to an export terminal on the Red Sea, bypassing the Strait of Hormuz and acting as a crucial relief valve for the global crude market during the US-Iran war.^[2] If the Houthis make good on their threat to close Bab el-Mandeb, that relief route is severed. A dual chokepoint — Hormuz closed by Iran, Bab el-Mandeb closed by the Houthis — would leave Gulf producers with no maritime exit for their oil.

Market Reaction: Energy Up, Equities Mixed

The market’s response on Monday reflected the competing signals of escalation and diplomatic possibility. Energy stocks moved higher in lockstep with crude: CVX gained 1.2% to $189.67, XOM rose 0.7% to $148.36, and COP added 0.8% to $115.68.^[5] The United States Oil Fund (USO) advanced 1.3% to $125.51.^[5] Defense contractors ticked higher, with RTX up 0.5% to $194.44 and NOC up 0.5% to $523.96.^[5]

The broader market was more ambivalent. The S&P 500 (SPY) closed down 0.15% at $742.21, the Dow (DIA) fell 0.56% to $517.89, and the Nasdaq 100 (QQQ) edged up 0.10% to $696.06.^[6] Semiconductor stocks managed a modest rebound, with SOXX up 0.45% to $524.14,^[6] though Deutsche Bank noted that the Philly semiconductor index remained in bear-market territory after leading global equity declines last week on escalating tensions and doubts over the AI trade.^[7]

Airlines, paradoxically, traded higher — UAL gained 1.8% to $117.52, AAL rose 1.1% to $15.14 — suggesting some investors are betting on a diplomatic off-ramp rather than pricing in sustained fuel-cost pressure.^[6] Gasoline prices at the US pump rose back to $4 per gallon, according to AAA, a level last seen on June 17 when the interim agreement was signed.^[2]

The Diplomatic Needle

Oil prices eased from their overnight peak above $91 after Iran’s Foreign Ministry spokesman Esmail Baghaei said negotiations with the US could be pursued based on Tehran’s interests.^[2] A senior Iranian official told Reuters that mediators had presented Tehran with a proposal for de-escalating the conflict and reviving the memorandum of understanding signed in June, which includes an end to hostilities across all fronts, including Lebanon.^[1]

The survival of a diplomatic track is the only thing currently keeping Brent below the $100 threshold. BNY’s Geoff Yu noted that Iran’s signals of continued military response alongside active mediation keep the conflict in a “managed but unstable phase,” with diplomatic risk keeping oil prices supported.^[8] Societe Generale observed that crack spreads in Asia and the US have outperformed as refined products stay tighter than crude, with tanker data confirming reduced Gulf shipping activity.^[8]

But the gap between rhetoric and reality is widening. The IRGC’s “not a single drop” declaration, the Houthi embargo, and Iran’s strikes on Kuwait and Bahrain all point to escalation, not restraint. As Energy Aspects founder Amrita Sen told CNBC, “The market is still quite complacent despite the price increase we have seen.”^[2] Sen warned that a substantial slowdown in Hormuz shipping combined with depleted global inventories could push oil above $100 per barrel.^[2]

What to Watch Next

• Hormuz transit numbers. The Kpler daily count is the cleanest leading indicator. Sunday’s eight vessels was a three-week low. If the count falls to zero or stays in single digits through the week, the supply shock intensifies regardless of what diplomats say.

• Houthi enforcement of the Saudi embargo. A declaration is not a blockade. The question is whether Houthi forces actually interdict Red Sea shipping or whether the threat alone is enough to halt Saudi pipeline exports. Watch for tanker incident reports from UKMTO and whether Saudi Arabia reroutes volumes.

• The diplomatic track. The June 17 interim agreement collapsed within three weeks. If mediators produce a new proposal, the market will discount it quickly — and will want to see whether Iran’s Foreign Ministry can override the IRGC’s harder line. The split between Baghaei’s openness to talks and the IRGC’s “not a single drop” statement is the internal fault line.

• Oil inventories and the $100 threshold. Brent’s May peak near $115 was driven by fear of prolonged disruption. The current setup is more real — Hormuz traffic is genuinely collapsing, not merely threatened. If inventories start drawing down visibly, the complacency Sen flagged could unwind fast.

• Inflation and Fed policy. Brent at $90-plus and gasoline at $4/gallon feed directly into the inflation outlook. Persistent hostilities could mean higher inflation, no Fed rate cuts, and possible hikes — a dangerous combination when US equities remain richly valued by traditional metrics.^[7] Any Fed commentary this week will be parsed for oil-driven inflation concerns.

• Big tech earnings as a cross-current. Google, Tesla, GM, IBM, and ServiceNow all report this week.^[7] With semiconductors already in a bear market^[7] and oil costs rising, the AI trade’s ability to absorb a geopolitical risk premium is being tested simultaneously from two directions.

This article is research commentary, not investment advice. It reflects a point-in-time assessment of publicly available information as of July 20, 2026.