The stock market rallied on June 18, 2026, as the U.S. and Iran reached a peace agreement, with the S&P 500 advancing 1.08% to close at 7,500.58, according to Reuters. The Nasdaq Composite climbed 1.91% on the same day. On Friday, June 19, the stock market closed in observance of Juneteenth, a federal holiday.
The relief rally came after President Trump and Iranian President Pezeshkian signed a memorandum of understanding aimed at ending their nearly four-month conflict, according to Sherwood News. The agreement includes a framework to reopen the Strait of Hormuz, the strategic waterway through which roughly 20% of the world’s oil and liquefied natural gas normally flows, according to the BBC.
Oil prices fell sharply on the deal. Brent crude futures declined 5% to close at $78.96 per barrel, the first time the benchmark dropped below $80 since early March, according to CNBC. The decline reflected investor expectations that reopening the Strait of Hormuz would ease global energy supply constraints and reduce inflation pressures, which had weighed on markets during the conflict.
Market analysts characterized the move as a classic relief rally. Reuters quoted market commentary noting that “markets are higher on a classic relief rally. We have a US-Iran deal that’s driving oil sharply lower. This is easing inflation fears.” The Nasdaq led gains, with the tech-heavy index climbing 1.91% on June 18, while the Dow Jones Industrial Average posted more modest gains, according to Reuters.
The deal represents a significant shift after months of escalating tensions. The interim agreement is designed to temporarily halt hostilities and reopen critical shipping lanes, though full normalization of oil flows is expected to extend through summer 2027, according to S&P Global. Iran has offered charge-free transit through the Strait for 60 days as part of the arrangement.
With the stock market closed on Friday for Juneteenth, the next full trading session will occur on Monday, June 22, 2026, according to Yahoo Finance. The market’s strong performance on Thursday reflected investor optimism that the geopolitical resolution could support economic growth and ease cost pressures that have constrained corporate earnings.
Sources
- Reuters — S&P 500 and Nasdaq gains on June 18, 2026; market commentary on relief rally and Iran deal impact
- CNBC — Brent crude futures decline to $78.96, first time below $80 since March
- Sherwood News — Trump and Iranian President Pezeshkian signed memorandum of understanding
- BBC — Strait of Hormuz significance (20% of world oil and LNG)
- Yahoo Finance — Stock market closure on June 19 for Juneteenth; next trading session June 22
- S&P Global — Oil supply normalization timeline and Iran’s charge-free transit offer
