Trainer Ronan McNally has been given a 12-year ban by Ireland's horse racing governing body.
McNally was found to have conspired with fellow trainer David Dunne to conceal his ownership of two horses.
Under improvement in form rules, McNally's Dreal Deal was disqualified from 2020 wins at Limerick and Navan.
He was also ordered to pay 50,000 euros (£44,000) in costs and return 13,400 euros (£11,800) of prize money by the Irish Horseracing Regulatory Board.
The long-running investigation into the improvement in form of horses linked to McNally included examination of Dreal Deal's victory at Navan in September 2020 when he was backed from 20-1 to 6-4 favourite.
A hearing in October upheld 10 of the 11 charges brought against McNally and ruled he had caused "serious damage to the interests of horse racing in Ireland".
McNally was also found to have achieved "a pattern of improvement in form of horses at a level previously unfamiliar to experienced and long-serving handicapping officials".
The Irish Horseracing Regulatory Board's investigation also ruled that McNally had conspired with Dunne to conceal his ownership of a number of horses.
County Meath-based trainer Dunne has been given a two-year ban with the final 18 months suspended for two years.
In addition to a 5,000 euros (£4,400) fine, Dunne must return almost 27,000 euros (£23,800) in prize money which covers 36 races in which All Class, Full Noise and Petrol Head ran in his name when McNally's ownership of the horses was concealed.
After the findings were published in December, McNally said he was "deeply disappointed and dissatisfied" with them and indicated he would contest the charges.
A sanctions hearing followed on 13 January, and the release of the official report on Tuesday said the Irish Horseracing Regulatory Board's referrals committee "regards the findings against Mr McNally as very serious".
"His offences strike at the integrity and the objective of having a level playing field for all who send horses out to race," added the report.
"They also involved a deception of the public, especially the betting public."
