** Shares of biopharmaceutical products developer 3SBio Inc 1530.HK slip 5.4% to HK$29.98, their lowest level since November 24

** Stock on course for the biggest one-day pct drop since November 21; top pct loser in Hang Seng Composite Index tracking healthcare stocks .HSCIH, which is down 1%

** 3SBio plans sale of 105.17 mln new shares to third paty investors in share placement, raising HK$3.12 billion ($400.49 million) for advancing clinical research in China and the United States on innovative drug candidates in the R&D stage to accelerate pipeline progress, among others

** The new shares will be issued at HK$29.62 apiece, or a 6.5% discount to Monday close of HK$31.68 each

** YTD, stock up 397%, Hang Seng Biotech Index .HSI up 80.1%

($1 = 7.7904 Hong Kong dollars)

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))