** Australian technology sub-index gains as much as 0.7& to hit its highest level since Oct 21

** The sub-index on track to record a fourth consecutive session of gains, if trend holds

** Sub-index tracks overnight gains on Wall Street

** Shares of Xero and NEXTDC add as much as 0.3% and 1.1%, respectively

** Sub-index up about 50% YTD, as at 0010 GMT, while benchmark ASX200 index up 8.4%

(Reporting by Echha Jain in Bengaluru)

((Echha.jain@thomsonreuters.com))