The ATP will not take any action against former world No.2 Alexander Zverev following allegations of domestic abuse against the German, the men's tennis governing body said.
In October 2021, the ATP launched an investigation into allegations levelled by his ex-girlfriend Olga Sharypova, who said in a magazine interview that Zverev was emotionally and physically abusive to her during their relationship.
Zverev has consistently denied all the allegations.
The ATP said the investigation's primary focus was related to alleged abuses taking place at the Masters event in Shanghai in 2019 but its scope also included alleged misconduct in Monaco, New York and Geneva based on reports.
"A major independent investigation into Alexander Zverev has found insufficient evidence to substantiate published allegations of abuse. As a result, no disciplinary action will be taken by ATP," it said in a statement.
"The investigation was carried out by The Lake Forest Group (LFG), a third-party investigator.
"LFG conducted extensive interviews with both Sharypova and Zverev, and 24 other individuals including family and friends, tennis players, and other parties involved with the ATP Tour."
The 25-year-old Zverev issued a statement saying he had maintained his innocence and welcomed the ATP investigation, adding he was grateful that the matter was finally resolved.
"From the beginning, I have maintained my innocence and denied the baseless allegations made against me," he said in a statement on Instagram on Tuesday.
"This decision marks a third, neutral, third-party arbiter who has reviewed all relevant information and made a clear and informed decision on this matter in my favour.
"In addition to the ATP's independent investigation, I have also initiated court proceedings in Germany and Russia, both of which I have won... My priority now is recovering from injury and concentrating on what I love most in this world - tennis."
After the 15-month investigation, which involved going through material on Zverev's electronic devices, the ATP said they were unable to substantiate allegations of abuse or determine that any player offences took place.
"This determination may however be re-evaluated should new evidence come to light, or should any legal proceedings reveal violations of ATP rules," it added.
"Zverev has consistently denied all allegations and supported ATP's investigation."
Zverev is currently ranked world No.14.