** Shares of Isle of Man-based gambling tech firm Playtech PTEC.L down 24.1% at 261p
** Stock was on track for its worst day since July of 2018
** Swedish online gaming co Evolution EVOG.ST named Playtech in a defamation lawsuit, accusing the UK-listed firm's unit of commissioning a 2021 report meant to damage its reputation and business operations
** Playtech says it stands by its decision to commission the report, which it says was to investigate "credible and repeated concerns" raised by operators, suppliers and regulators about Evolution's activities in some markets
** PTEC, however, said allegations that it engaged in a smear campaign is "wholly untrue"
** Evolution says PTS paid 1.8 mln pounds ($2.42 mln) to private spy firm Black Cube in 2021 to "fabricate a report they knew would have extremely harmful repercussions"; it says report resulted in multi-bln dollar damage to Evolution
** PTEC says it welcomes court review of the report and its findings
** Including session's losses, stock down ~17.56% YTD
($1 = 0.7451 pounds)
(Reporting by Ankita Bora in Bengaluru)
((Ankita.Bora@thomsonreuters.com))