Nasdaq Tumbles 2.4%. A Chip Selloff Grips Wall Street.

A selloff in highflying semiconductor stocks gripped Wall Street Tuesday morning. The Nasdaq Composite tumbled 2.4%. The S&P 500 fell 1.6%. The Dow dropped 371 points, or 0.7%. The Nasdaq 100 was on pace to shed more than $1 trillion in market cap.