Quanta Services is trading at $642.72, down 5.96%, in after-hours trading, with no clear company-specific catalyst for the October 5 drop surfaced in the available search results.

  • The company’s listed recent press release was dated September 9.
  • The market picture was mixed: the S&P 500 and Dow were higher while the Nasdaq was lower. No volume or activity-level data was provided.