** Shares of Dropsuite DSE.AX rise 29.8% to A$5.71, their highest since May 16, 2013
** Stock posts its biggest intraday gain since July 3, 2020
** Cloud services provider says U.S. based IT management software firm NinjaOne will buy co for A$420 million ($263.05 million) in cash
** Offer price of A$5.90 per share represents a 34.1% premium to co's last close
** About 2.2 mln shares change hands, vs the 30-day average of around 48,000
** Stock up 23.1% this year, including the day's move
($1 = 1.5967 Australian dollars)
(Reporting by Sameer Manekar in Bengaluru)
((Sameer.Manekar@thomsonreuters.com;))