Oil Shock and Iran Threats Send Wall Street Sliding for a Third Straight Day

Markets Rattled as US-Iran Conflict Escalates

Wall Street has had a rough stretch, and the US-Iran conflict is squarely at the center of it. On Tuesday, August 18, US stock futures extended a multi-day slide as fresh geopolitical flashpoints stoked fears of higher inflation and prolonged energy disruptions. Futures on the Dow Jones Industrial Average were essentially flat, while S&P 500 futures declined 0.4% and Nasdaq-100 contracts retreated 1.1%, leading the major indexes lower after a downbeat start to the trading week.

The catalyst was blunt and alarming. Oil prices climbed to their highest level in over two weeks after President Trump said he intends to inflict more economic pain on Iran and threatened to "bomb" Oman if it interferes with the US's plans for the Strait of Hormuz. That kind of rhetoric doesn't stay confined to diplomatic channels — it moves markets, and fast.

Oil Prices Surge as Hormuz Shipping Collapses

The Strait of Hormuz is the pressure point that keeps rattling global energy markets. In 2025, roughly 25% of the world's maritime trade in crude oil and petroleum products, as well as roughly 19% of liquefied natural gas, passed through the Strait. When that corridor is threatened, the ripple effects are immediate and global. Commercial shipping traffic through the vital waterway has plunged, with vessel transits dropping from 31 the previous weekend to just five.

Brent crude futures, the international benchmark, hit $91 per barrel, and US benchmark West Texas Intermediate crude rose to $84 per barrel as the US Strategic Petroleum Reserve plunged to its lowest level since 1982. That's a dangerous combination: surging crude prices on top of a depleted emergency stockpile leaves the US with fewer tools to cushion consumers from energy shocks. Crude oil held in the US Strategic Petroleum Reserve fell by approximately 5.3 million barrels during the previous week alone.

Iran's Threat to Escalate Keeps Investors on Edge

The geopolitical picture darkened further when Iran signaled it wasn't backing down. A senior Iranian official told Reuters that the country may shift to an offensive policy rather than a defensive one if diplomacy fails, adding that Iran will escalate tensions in the Strait of Hormuz — the critical passageway for oil that Iran controls — and the wider Middle East region. That warning alone was enough to send traders reaching for the exit.

Adding to the pressure, the 10-year and 30-year Treasury yields extended their gains amid concerns about growing national debt, with the 30-year yield rising 5 basis points to 5.31%, hitting its highest level since June 2007. Rising yields make borrowing more expensive across the board — for businesses, homebuyers, and the federal government — and they tend to drag on stock valuations, particularly in the tech-heavy Nasdaq.

What Comes Next for Markets

The broader market context makes this moment particularly precarious. As one senior economist at Interactive Brokers put it, "Crude prices are rising on renewed geopolitical tensions triggered by President Trump threatening Oman with military strikes and communicating that he is in no rush to end the Iran war." That's not the kind of environment where investors feel confident deploying capital.

Investors are now anticipating the Federal Reserve's next policy move and a slate of retail earnings, with fewer market-moving economic data releases on the calendar. The Fed faces a genuinely difficult hand: inflation pressures from energy costs are building just as the economy needs breathing room. Crude oil isn't priced based on where it was produced but on global benchmark prices that reflect worldwide supply and demand — and as one energy executive put it, "Independence doesn't mean price security or price independence because oil is a globally traded commodity." Until there's a credible path toward de-escalation in the Middle East, markets are likely to remain hostage to every new headline out of Tehran and Washington.