** Shares of Australia's Cogstate CGS.AX rise as much as 7.3% to A$2.36, their highest level since December 22
** Stock hits biggest intraday pct gain in one month
** Biotech co posts HY revenue of $26.9 million, up from $23.9 million a year ago
** Stock rose more than two-folds in 2025, down 2.7% YTD
(Reporting by Aamir Sheik Khalid in Bengaluru)
((Aamir.SheikKhalid@thomsonreuters.com))