C3.ai tumbles after weak preliminary quarterly results

** AI software maker C3.ai's AI.N shares fall nearly 27% to $16.08 premarket

** D.A.Davidson downgrades stock to "underperform" from "neutral," slashes PT to $13 from $25 - 41% downside from Friday's close

** Cites AI’s preliminary results, which came in well below guidance, alongside a restructured sales and services organization with new regional leadership

** With C3.ai in the process of finding a successor to CEO Tom Siebel, more disruption is on the horizon ... view business trends as likely to get worse before they get better — D.A.Davidson

** Average rating from 16 analysts is "hold"; median PT is $27.5 - data compiled by LSEG

** Up to Friday's close, shares down nearly 36% YTD