Trader Talk host Kenny Polcari argues that investors' "knee-jerk" reaction to tariffs is the real problem facing the market.

U.S. stock indexes are slumping further from their records Thursday as Wall Street’s frenzy around artificial-intelligence technology weakens some more. The S&P 500 was down 1% in late trading and on track for its fifth drop in six days after setting an all-time high set last week.