New York Stock Market, U.S.-Iran negotiations break down leading to a decline... Middle East tensions escalate

The New York stock market opened broadly lower after the breakdown of the US-Iran ceasefire negotiations and the US’s blockade of maritime traffic entering and exiting Iranian ports. As tensions in the Middle East flare up again, investors have been cutting risk assets and reassessing the impact of soaring energy prices on the global economy and prices.

As of 9:39 a.m. Eastern Time on the 13th, the Dow Jones Industrial Average on the New York Stock Exchange was down 337.79 points (0.70%) from the previous trading day, at 47,578.78 points. The S&P 500 fell 21.54 points (0.32%) to 6,795.35; the Nasdaq Composite declined 78.70 points (0.34%) to 22,824.19. The US and Iranian delegations held around 21 hours of extensive negotiations from the early hours of the 11th to the 12th, but were unable to reach a ceasefire agreement.

After the talks broke down, the US immediately announced that starting at 10:00 a.m. on the 13th, it would impose a blockade on all maritime traffic entering and exiting Iranian ports. The move is seen as a response to Iran’s long-standing use of the potential blockade of the Strait of Hormuz as bargaining leverage in negotiations. The US aims to pressure Iran’s logistics and financial flows by controlling maritime routes. The US military said the measure applies to all ships, regardless of their flag state, and warned that vessels entering or leaving the blockade area without approval may be intercepted, ordered to change course, or seized. Tellimer’s emerging markets strategist Hasnain Malik said that the range of future scenarios is once again widening—spanning from further negotiations to the renewed outbreak of military conflict, with multiple possibilities now on the table.

By industry, nearly all sectors fell except energy. As geopolitical risks increased and international oil prices jumped higher, airlines and cruise companies most sensitive to fuel-cost burdens were hit first. United Airlines fell 2.99%, while Carnival dropped 3.72%. Meanwhile, among individual stocks, biotech company Revolution Medicines performed strongly. The company announced that its pancreatic cancer treatment drug Dazlursalaclib achieved results in Phase III clinical trials, and its share price surged 39.92%. The company explained that patients receiving existing cancer treatments have a survival period of 6.7 months, while the Dazlursalaclib dosing group extended to 13.2 months. SanDisk also rose 3.64% after news that it will be included in the Nasdaq 100 index starting on the 20th.

European stock markets also weakened in sync for the same reasons. The Euro Stoxx 50 index traded at 5,873.18 points, down 0.89% from the previous trading day; France’s CAC 40 fell 0.480%, Germany’s DAX declined 0.97%, and the UK’s FTSE 100 dropped 0.41%. International oil prices surged sharply. In the same period, the near-month contract—West Texas Intermediate crude oil for May 2026 delivery—was quoted at $103.51 per barrel, up 7.19% from the previous trading day. The Strait of Hormuz, a critical passage for global crude-oil transportation bordering the Middle East, has seen tensions in the region escalate, which often immediately triggers concerns about potential disruptions to crude-oil supply and is reflected in prices. This trend suggests that volatility in stock markets and oil prices may continue for some time, depending on whether the US and Iran return to the negotiating table or sanctions and military tensions further escalate.