** Shares of Australia's Brookside Energy BRK.AX rise as
much as 38.5% to A$0.018
** Stock on track to post highest daily pct gain since
April 2021, if trends hold
** Co says it will undertake an on-market buyback of up to
500 mln ordinary shares
** Adds cash costs for the buyback expected to be A$6.5
mln($4.3 mln)
** Stock hits highest since August 2022
** Stock last up, extending YTD gains to 36.4% from 18.2% at
last close
($1 = 1.5122 Australian dollars)
(Reporting by Rishav Chatterjee in Bengaluru)
((Rishav.Chatterjee@thomsonreuters.com;))