** Shares of Australia's bourse operator ASX.AX rise as much as 4.2% to A$59.95, their highest level since September 24

** Stock set for its strongest trading session since April 10, if current trends hold

** Brokerage Macquarie upgrades stock rating to "outperform" from "neutral"; hikes price target to A$64 per share from A$63

** Macquarie says CBOE Global Markets CBOE.Z announcing intention to sell their Australian ops on October 31 confirms the Australian market is too small to support competition, which could provide pricing support for ASX in medium term

** With momentum around equities and futures volumes, at current multiples we see valuations as attractive - brokerage

** Macquarie's upgrades incorporate CAPEX and OPEX forecasts at upper end of FY26 and FY27 guidance for stock

** Day's gains cut stock's YTD losses to 8.4%

(Reporting by Shivangi Lahiri and Sneha Kumar in Bengaluru)

((shivangi.lahiri@thomsonreuters.com))