Tennis accounted for nearly three-quarters of all suspicious betting identified by a leading sports gambling watchdog in 2015.
Essa says it identified 100 cases with 73 of them occurring in tennis matches.
Last month a BBC and BuzzFeed News investigation found evidence of widespread suspected match-fixing among leading players over the past decade.
Essa issues alerts to regulated bookmakers across Europe when irregular activity is spotted on a match.
If several bookmakers confirm that they are encountering suspicious betting patterns, the watchdog sends a formal warning to the sport's governing bodies.