The Southern Bangkok Criminal Court Monday handed down a commuted three-year jail term to Xavier Andre Justo, a Swiss national linked to an unravelling Malaysian government scandal.
Justo, 49, pleaded guilty to blackmailing his former employer PetroSaudi and was told that without his confession, he would have served six years behind bars.
The Swiss has been remanded in a Bangkok prison since being arrested in Koh Samui in June.
Police said Justo demanded 90 million baht from PetroSaudi in exchange for not disclosing confidential information to rival companies in 2013.
But he denied asking for nearly 10 million ringgit more (86.4 million baht) in a blackmail attempt regarding the Malaysian state investment fund, 1Malaysia Development Berhad (1MDB).
Alleged connections between PetroSaudi and 1MDB surfaced last month, with the media reporting nearly $700 million (24.8 billion baht) in 1MDB funds were transferred in 2013 to bank accounts apparently controlled by Malaysian Prime Minister Najib Razak before general elections. Mr Najib has denied any wrongdoing and called the leaking of documents part of a plot against him.
The controversy has weakened the Malaysian ringgit to its 1997/98 Asian Financial Crisis level and has undermined the credibility of Mr Najib, who chairs the fund's advisory board.
PetroSaudi reported to Thai police in May this year, after documents showing 1MDB's financial mismanagement were published on a news website, run by Clare Rewcastle Brown, sister-in-law of former UK prime minister Gordon Brown.