** Shares of Ventia Services rise as much as 3.3% to A$3.565, their highest since Dec. 13

** Infrastructure provider says it signed a five-year agreement with Telstra to support digital infrastructure

** Ventia sees partnership to generate over A$400 million ($249.24 million) in annual revenue for co

** Stock posts its biggest intraday pct gain since Dec. 17

** VNT up 13.1% YTD

($1 = 1.6049 Australian dollars)

(Reporting by Adwitiya Srivastava in Bengaluru)

((Adwitiya.Srivastava@thomsonreuters.com))