Five9 is trading $28.38, 16.87% down in pre-market on November 6, with its Q4 non-GAAP EPS outlook below consensus the clearest catalyst. - Its November 5 results prompted a sharp after-hours selloff, although third-quarter revenue and adjusted earnings beat estimates. - Q4 non-GAAP EPS outlook was $0.88–$0.92, versus $0.99 consensus. - Five9 announced a $325 million cash acquisition of Level AI; reporting pointed to the weaker profit outlook as the immediate concern.