Nasdaq Sets Record High as U.S.-Iran Talks, Diesel Export Ban Weigh on Oil

The Nasdaq Composite closed at a record high on Tuesday, Sept. 22, 2026, rising 0.5% for a fourth straight session as traders assessed U.S.-Iran diplomacy and its impact on energy markets. The Dow Jones Industrial Average fell 0.4%, and the S&P 500 ended slightly lower, about 0.7% below its record. President Donald Trump said U.S. and Iranian representatives met for three hours alongside the U.N. General Assembly in New York, calling it a "very good meeting." Oil prices were mixed: November Brent gained about 0.4% to near $99.60 a barrel, while West Texas Intermediate fell 0.6% to $89.97. European gasoil futures jumped more than 4% after Trump backed a possible ban on U.S. diesel exports. Treasury Secretary Scott Bessent said the administration is weighing a full or partial prohibition. The dollar hit a near two-month trade-weighted high on hawkish Federal Reserve expectations; the euro, yen and pound declined.