** Shares of Australia's Steadfast Group SDF.AX rise as much as 2.31% to A$5.31, their highest level since June 11

** Shares mark their strongest intraday pct gain since June 25

** The insurance broker says U.S.-based investment firm KKR & Co KKR.N has joined a consortium of specialty insurance distributor Amwins Group and investment company Dragoneer Investment Group, which had previously offered to acquire Steadfast

** Deal values Steadfast at A$7.7 billion ($5.33 billion) in cash

** Adds Amwins and Dragoneer have confirmed that KKR's participation will not impact the transaction timetable to which the parties are currently working

** Stock down 0.3% YTD, including session's moves

($1 = 1.4453 Australian dollars)