** ReadyTech Holdings RDY.AX plunges 15.8% to A$2.78; set for weakest trading session to-date

** Stock slid as much as 19.4% to A$2.66 in early trade

** Software firm logs HY loss attributable of A$18.9 mln ($11.96 mln) vs year-ago profit of A$2.3 mln

** More than 595,000 shares traded, ~19x the 30-day avg

** RDY falls ~11% YTD

($1 = A$1.5808)

(Reporting by Nikita Maria Jino in Bengaluru)

((Nikita.Jino@thomsonreuters.com;))