The International Tennis Integrity Agency is investigating two matches at Wimbledon over possible irregular betting patterns.
The ITIA, which is responsible for safeguarding the integrity of professional tennis worldwide, received two alerts from the betting industry during the championships at the All England Club.
Alerts can be for match-fixing, but also incorrect odds-setting, well-informed betting, player fitness, fatigue or form as well as playing conditions and personal circumstances.
A spokesman for the ITIA said: "Any alert reported to the ITIA is recorded, assessed and followed up as an indicator that something inappropriate may have happened.
"It is important to note that an alert on its own is not evidence of match-fixing. Where analysis of a match alert does suggest corrupt activity, the ITIA conducts a full and confidential investigation."
The ITIA said it was not able to provide more details on the matches being investigated, but German newspaper Die Welt reported a first-round singles match and a first-round men's doubles match were the ties being looked at.
In a statement to the PA news agency, a spokesperson for the All England Club said: "The integrity of the sport is of the utmost importance to everyone at Wimbledon.
"We continue to invest in additional measures to support the integrity operation onsite during the Championships and we work closely with the ITIA both at the Championships and throughout the year."
Alerts are more common outside of grand slam tournaments, but one was recorded at the delayed 2020 French Open.
No alerts occurred at Roland Garros this year or at the Australian Open in February, with the majority coming from ITF tournaments.
Before Wimbledon got under way last month, the ITIA had received 34 match alerts through its confidential memoranda of understanding with the regulated betting industry in 2021.