** Shares of 361 Degrees International 1361.HK drop 19.7% to HK$5.56, their lowest point since March 25
** Stock on track for the biggest one-day pct decline since September 2017
** Chinese sports footwear and apparel maker plans sale of 100 mln new shares to key shareholder, raising HK$618 mln ($78.86 mln) for overseas network expansion and working capital
** Says the new shares will be issued at HK$6.18 apiece, representing a 10.7% discount to Monday's close of HK$6.92
** Key shareholder will buy the new shares on completion of sale of the same amount of existing shares at the same price to third party investors
** YTD, stock down 5.1%, while benchmark Hang Seng Index .HSI up 1%
($1 = 7.8365 Hong Kong dollars)
(Reporting by Donny Kwok)
((donny.kwok@thomsonreuters.com))