** Shanghai MicroPort MedBot Group 2252.HK slips 13.2% to HK$15.6, lowest since April 22

** Stock set for biggest one-day pct drop since April 7; top pct loser on Hang Seng Biotech Index .HSHKBIO

** Chinese surgical robots developer and maker plans sale of 25.14 mln new H-shares to raise HK$389.6 mln ($49.9 mln) for products upgrade and commercialization and replenishing working capital

** Issue price of HK$15.5 represents 13.8% discount to Tuesday's close

** Co says controlling shareholder plans to dispose 30.16 mln existing shares at HK$15.5 apiece to third party investors

** YTD, stock up ~73%

($1 = HK$7.8076)

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))