The Tennis Integrity Unit announced Friday that it received alerts of suspicious betting on 48 matches between January and March.
The TIU received only 31 alerts during the same time period last year, so this year marks a 55% increase. However, the 48 alerts still represent only 0.2% of the 24,110 matches played around the world.
One alert involved a match in the Australian Open, and one other was from the WTA tour. The other 46 alerts originated from lower levels of professional tennis.
The spike comes amid increased scrutiny on the sport following a BBC and BuzzFeed investigation, published in January, alleging wide spread match–fixing that tennis authorities had failed to properly deal with.
Just days after the investigation was published, Pinnacle Sports, a sports gambling website, halted betting during an Australian Open match after concerns that the contest might have been fixed.
A match alert can potentially signal match–fixing, but the TIU listed incorrect odds-setting, player fitness, playing conditions and personal circumstances as other possible reasons for unexpected activity.
The TIU did not name any specific matches or players involved. The TIU said a full investigation will follow if "analysis does suggest corrupt activity."