Property developer Owen O'Callaghan has said the investigation by the Mahon Tribunal has had a devastating effect on himself and his family.
Mr O'Callaghan today finished his testimony that was spread over 39 days.
He again rejected claims by Tom Gilmartin that he had paid bribes to senior Fianna Fáil politicians including former Taoisigh Bertie Ahern and Albert Reynolds.
Mr O'Callaghan said he had made legitimate political donations and remained a strong supporter of Fianna Fáil.
The Planning and Payments Tribunal is expected to conclude next week after ten years of evidence with testimony from the widow and the son of the late Liam Lawlor.