Tennis faces "very significant" integrity problems caused by the sharp increase in internet betting, an independent report concluded in its interim finding on Wednesday with one investigator describing it as a "tsunami" at its lower levels.
The Interim Report of the Independent Review of Integrity said its two-year investigation had not revealed widespread corruption at the highest levels of the professional game globally although "there is nonetheless evidence of some issues at these levels".
The Review was commissioned by the sport's major bodies (the ATP, WTA, ITF and Grand Slam Board) in 2016 following a report by the BBC and BuzzFeed News which claimed 16 players ranked in the world's top 50 had been flagged to the Tennis Integrity Unit (TIU) over suspicions that matches had been thrown.
However, the panel chairman, Adam Lewis, said: "Match-fixing is unlikely at the level of grand slam. All the indicators are clear the problem is low."
Among the report's recommendations are a greater monitoring of the lower levels of the game, with one investigator saying there is a "tsunami" of problems, plus a review of appearance fees and the ranking system.
The report also called for greater education among players, the elimination of gambling sponsorships, changes to integrity rules and for the TIU to be beefed up and be truly independent.
"The integrity problems are greatest where prize money relative to costs, prospects of advancement, pubic interest and attention, and financial resources of tournaments are lowest," it said.
Tennis operates under a pyramid system with young players competing in Futures and then Challenger tournaments of increasing value under the main tour.
The panel said the advent of online betting and the sale of official live scoring date have greatly exacerbated the problem and recommends that the ITF ends its data sale agreement at $15,000 Futures events, and probably at other ones as well.
The report dates many of the problems to the 2011 agreement between the ITF and data company Sportradar for the sale of live scoring data. A further agreement followed in 2015.
The panel recognised that any change in the system would financially penalise the ITF, which it said should be compensated for by the other governing authorities.
The report added that there are no simple solutions but called on the sport "to address and limit the betting markets that ultimately drive, and give expression to, the problem and to improve the systems of preventing and disrupting breaches of integrity, and for detecting and sanctioning them when they occur."
The report paints a picture of financial privation among many of the sport's 15,000 professionals, with many at the lowest level struggling to cover the costs of competing.
This, the report said, made betting on matches more attractive to players, many of whom admitted knowledge of match-fixing.
A survey of 3,200 players found that 16 percent indicated they had first-hand knowledge of players betting on matches, 11 percent knew of inside information being provided and 14.5 percent of match-fixing. Of these, 35 percent said they had knowledge of more than one instance.
But Lewis said that in many cases the scale of the betting was small, with players seeking the cost of a flight or with relatives, who often double as financial backers, seeking to offset costs.
The three-person panel took statements from 200 key stakeholders, conducted more than 100 interviews and collected more than 3,200 survey responses.
The panel did not look at whether any individual player breached integrity and only players who were subject to the disciplinary process are named in its report.
Tennis' governing bodies have committed to implementing the report's final findings after a period of consultation until the end of June. The final report will be published later this year.