The United States seized an Iranian-flagged cargo ship in the Gulf of Oman on Sunday, escalating tensions that sent crude prices higher while U.S. Stocks gave back only a fraction of their recent record-breaking rally.
President Donald Trump announced the seizure in a Truth Social post, stating the vessel was under U.S. Treasury sanctions due to prior illegal activity and that the U.S. Had full custody of the ship and its contents. He also warned that all power plants and bridges in Iran would be destroyed if Tehran did not agree to a U.S.-brokered deal. The move came after Iran declined to join a new round of peace talks in Pakistan arranged by the United States.
By Monday morning, the Dow Jones Industrial Average was down 115 points, or 0.2%, the S&P 500 had slipped 0.4% from its all-time high, and the Nasdaq Composite was 0.7% lower. Despite the geopolitical shock, losses remained contained, with traders betting that a diplomatic resolution would eventually emerge. David Wagner, head of equities at Aptus Capital Advisors, told CNBC that “the war with Iran is now in the rearview mirror for the market,” reflecting confidence that tensions would not derail the broader equity rally.
Oil prices reacted more sharply. Brent crude futures climbed 5.1% to $94.98 per barrel, while West Texas Intermediate rose 5% to above $88 per barrel. Though significant, the gains were modest compared to earlier spikes in the conflict, when Brent briefly exceeded $119 per barrel. The increase reflects concerns that Iran may continue to block tankers from exiting the Strait of Hormuz, undermining global oil flows.
The Strait of Hormuz remains a flashpoint. Iran declared the waterway reopened to commercial traffic following a separate ceasefire with Lebanon, but by Saturday, state media reported that vessel traffic had been restricted again, accusing the U.S. Of failing to meet its obligations. Trump has insisted the U.S. Blockade will stay in place until Iran agrees to American demands, setting up a direct contradiction with Tehran’s position.
For more on this story, see U.S. Navy seizes Iranian ship, Iran closes Strait of Hormuz, oil prices jump.
Still, market movements suggest investors see room for compromise. The muted equity losses, despite the seizure and rhetoric, indicate that many traders believe a U.S.-Iranian agreement restoring oil flows is still possible — and in both nations’ economic interests. This outlook is reinforced by the fact that the S&P 500 remains above its pre-war levels, even after the latest escalation.
Sector performance revealed a stark divergence. Semiconductors continued their historic run, with the iShares Semiconductor ETF (SOXX) logging its 14th consecutive day of gains — the longest streak since June 2014 — and on pace for its best month ever, up roughly 25% since inception in July 2001. The Philadelphia Semiconductor Index posted its strongest month since February 2000. Airlines and cruise lines, meanwhile, bore the brunt of higher fuel costs: Norwegian Cruise Line Holdings fell 5.1%, Carnival dropped 1.4%, United Airlines slipped 2.4%, and American Airlines lost 5% after rejecting a merger overture from United.
On the gainers’ side, TopBuild, a distributor of insulation and building products, jumped 16.4% after QXO announced a $17 billion acquisition that would make it the continent’s second-largest publicly traded building products distributor. QXO’s own stock fell 8.2% on the news.
This follows our earlier report, U.S. Navy Seizes Iranian Cargo Ship in Gulf of Oman, Triggering Market Sell-Off.
Underlying the market’s resilience is a strong earnings foundation. U.S. Corporations reported robust profits for the first three months of 2026, fueling expectations for continued growth. Wagner argued that the market’s advance is not overextended, insisting that earnings growth and valuation expansion — not speculation — are driving the rally, and that there remains “a pretty good landscape for equity market returns in the near future.”
Why did stocks fall only slightly despite the seizure of an Iranian ship?
Traders believe the U.S. And Iran will eventually reach a compromise, limiting the perceived risk of prolonged conflict and keeping equity losses contained despite the escalation.
How are oil prices reacting to the renewed tensions, and what does this suggest about market expectations?
Brent crude rose 5.1% to $94.98 per barrel, a modest increase compared to earlier wartime highs above $119, suggesting investors still see a path to a deal that could restore oil flows from the Persian Gulf.
