** Shares of online ride hailing platform operator CaoCao Inc 2643.HK fall 5.8% to HK$33.6, on track for the biggest one-day pct decline since December 18

** Stock sinks to the lowest since January 22 on the third straight session of fall

** Company plans sale of 12 mln new shares, representing 2.06% of the enlarged share capital, to third party investors, raising HK$389.5 mln ($49.93 mln) for development of robotaxi business, expanding enterprise services and for working capital

** Says the new shares will be issued at HK$32.46 each, or 8.97% discount to Tuesday's close of HK$35.66

** YTD, stock up 12.8%, Hang Seng TECH Index .HSTECH up 6.1%

($1 = 7.8007 Hong Kong dollars)

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))