** Shares of Australia's Austin Engineering ANG.AX rise as much as 13.4% to A$0.318, their biggest intraday gain since March 21

** Highest level since September 10

** Engineering co announces on-market share buyback of up to 10% of its stock to be undertaken over the coming 12 months

** Stock is down 37.8% YTD, including the session's moves

(Reporting by Anjali Singh in Bengaluru)

((anjali.singh2@thomsonreuters.com;))