Nasdaq, S&P 500 Slide on Iran Sanctions, U.S.-Canada Tariff Worries

Stocks were mixed Monday as investors weighed new U.S. economic sanctions against Iran, failed U.S.-Canada trade talks, reciprocal tariff threats, and upcoming earnings from Nvidia ($NVDA), along with the Federal Reserve's annual Jackson Hole symposium.
Treasury Secretary Scott Bessent was expected to reveal details of the administration's sanctions plans against Iran later Monday, after President Trump threatened the country with "economic D-Day." The Fed's Jackson Hole symposium begins Thursday, with Chairman Kevin Warsh set to deliver keynote remarks Friday.
Daniela Hathorn, senior market analyst at Capital.com, said markets will look for clarity on Warsh's inflation assessment and the broader "regime change" he has advocated at the Fed, though he may focus more on the Fed's longer-term philosophy than explicit signals for September policy.
In addition to Nvidia, Intuit ($INTU), Salesforce ($CRM), and Marvell Technology ($MRVL) are also scheduled to report earnings this week. Stocks closed higher Friday, rebounding from earlier losses, but major indexes still finished the week lower amid volatile Treasury yields and heightened Middle East tensions.