US Markets Volatile as Trump Ends Iran Ceasefire

Global financial markets experienced extreme volatility between July 8 and July 9, 2026, driven by escalating military conflict between the United States and Iran. The instability began after Iran attacked commercial shipping in the Strait of Hormuz, including a Qatari LNG carrier and a Saudi oil tanker. In response, the United States struck 90 Iranian targets, prompting retaliatory strikes from Iran on U.S. military sites in Bahrain, Qatar, and Kuwait.

Markets initially stabilized on July 9 when President Donald Trump suggested the fighting would not result in "long-term" military action. This brief optimism, combined with surging demand for AI memory, boosted semiconductor firms like Micron Technology, which announced a $3 billion U.S. supply chain investment. However, the recovery was short-lived; later that day, Trump declared the temporary ceasefire was "over" and characterized ongoing negotiations as "wasting their time," ordering a new night of airstrikes.

These developments triggered sharp declines in the Dow Jones Industrial Average and S&P 500, particularly impacting airlines and housing. Investors fear a full-scale war could block the Strait of Hormuz, spiking inflation and forcing the Federal Reserve to raise interest rates. Separately, the business sector saw AstraZeneca lose £20 billion in value after a heart drug trial failed, while Vertex Pharmaceuticals agreed to acquire Crinetics Pharmaceuticals for $10 billion.