** Shares of Australia's Appen APX.AX rise as much as 13.2% to A$1.5, marking their biggest intraday pct gain in one week

** Data services provider posts FY underlying EBITDA before FX of $12.2 mln, up from $3.5 mln last year

** Sees FY26 underlying EBITDA (before FX) margin of ~5% to 10%, compared to 5.3% reported for FY25

** Sees FY revenue of $270 mln to $300 mln, up from $230.8 mln group operating revenue in FY25

** Stock last up 11.8%, with YTD gains of more than 80%

(Reporting by Sneha Kumar in Bengaluru)

((Sneha.kumar@thomsonreuters.com;))