Nasdaq, S&P 500 Rebound on U.S.-Iran Deal Signing

U.S. equity markets surged on June 18, 2026, with the Nasdaq and S&P 500 experiencing significant rebounds following the official signing of a landmark deal between the United States and Iran. The positive market reaction reversed earlier declines across major indices. The agreement, which concluded extended negotiations, is widely interpreted by investors as a de-escalation of geopolitical risks. This positive sentiment spurred broad-based buying across equity sectors, contributing to the day's robust gains. The immediate market reaction underscores investor confidence in the potential for increased stability and reduced uncertainty in international relations, particularly concerning global energy supplies and trade routes.