Koellerer has been banned from all pro tennis with immediate effect
Former world number 55 Daniel Koellerer has been given a life ban from the sport for match-fixing.
The 27-year-old Austrian, currently ranked 385th, has been found guilty of three charges under the Uniform Tennis Anti-Corruption Programme.
They include "contriving or attempting to contrive the outcome of an event" between October 2009 and July 2010.
"The life ban applies with immediate effect," said the anti-corruption Tennis Integrity Unit (TIU).
"Mr Koellerer is not eligible to participate in any tournament or competition organised or sanctioned by the governing bodies of professional tennis."
Koellerer, who was also fined $100,000 (£61,000), has the right to appeal at the Court of Arbitration for Sport (CAS).
Koellerer's manager, Manfred Nareyka, disputed the verdict and confirmed the Austrian is considering an appeal.
"This is a massive shock. This investigation has now been going on for a year and a half. It has affected him making a living," he said.
"There is no proof. I distance myself from any form of match-fixing."
He added of a possible appeal: "We're looking into it now. He isn't sure if he can afford the legal costs. He is going to become a father in July. It is very difficult."
The TIU has not specified which matches Koellerer manipulated and said no details of the hearing or decision will be made public.
The TIU was established by the International Tennis Federation (ITF) and the ATP and WTA Tours to protect the sport from corruption and betting scandals.
All players must sign up to the Uniform Tennis Anti-Corruption Programme.