Why Is Five9 ($FIVN) Stock Down -19.45% Today? FIVN shares plunged roughly 19.45% to about $27.50, down from a prior close of $34.14. The primary catalyst was

Why Is Five9 ($FIVN) Stock Down -19.45% Today? FIVN shares plunged roughly 19.45% to about $27.50, down from a prior close of $34.14. The primary catalyst was weak fourth-quarter and full-year profit guidance, which overshadowed a modest third-quarter beat.