By Agence France-Presse
Xavier Justo was jailed last August for attempting to blackmail his former employer PetroSaudi International, a Saudi oil firm allegedly involved in corrupt dealings with Malaysian fund 1MDB.
Malaysian Prime Minister Najib Razak, who launched the scandal-mired 1MDB, has been besieged by allegations that he and his cronies looted billions of dollars from it, prompting calls for him to resign.
According to Thai police Justo was jailed after demanding around $2.5 million from PetroSaudi to return sensitive company data he claimed to have taken before leaving the firm in 2011.
He was arrested on the Thai island of Koh Samui in June 2015 and handed a three-year sentence.
But on Wednesday his lawyer said he will get out early after a mass prisoner amnesty.
"After he is released he will be sent to Thai immigration and then sent back to Switzerland," Worasit Piriyawiboon told AFP, adding that his precise release date had not been set.
Malaysia has been gripped by the financial fiasco for over a year, with investigations now underway in several countries, including Switzerland and the United States.
Allegations that hundreds of millions of dollars in 1MDB money went missing from the PetroSaudi deals have swirled.
The US Justice Department -- which has filed lawsuits to seize assets it says were purchased with stolen 1MDB money -- says the fund was bilked with the involvement of an unnamed top Malaysian official.
A Malaysian Cabinet official has since admitted that individual was Najib.
Najib, 1MDB and PetroSaudi deny wrongdoing.
Last month tens of thousands of protesters gathered in Kuala Lumpur to demand Najib's resignation.