By Agence France-Presse
Yeo Jiawei, a Singaporean former wealth manager with Swiss bank BSI, was convicted after a 12-day trial of witness-tampering and obstructing the city-state's 1MDB-linked investigations. He will be sentenced on Thursday.
"I find the accused to be inconsistent and an unreliable witness," said Judge Ng Peng Hong in delivering his verdict.
Yeo, 33, is also charged with money-laundering, cheating and forgery but will be tried next year on those counts.
Allegations that huge sums were misappropriated from the Malaysian state fund through money-laundering have triggered a massive corruption scandal which has embroiled Malaysian Prime Minister Najib Razak.
Singapore, a regional financial hub known for its transparency and strong stance against corruption, last year launched a probe into alleged unlawful fund flows linked to 1MDB.
BSI and another Swiss bank, Falcon, were kicked out of the city-state this year for what regulators called massive lapses in financial controls. Swiss banks were allegedly used to transfer illicit funds.
Two other former private bankers from BSI have also been jailed in Singapore for fraud in connection with the case.
It was revealed during Yeo's trial that he worked closely with Malaysian financier Low Taek Jho, also known as Jho Low, a family friend of Najib.
Najib founded the 1MDB fund while Low helped set it up and played a key role in its decisions. Both men have strongly denied any wrongdoing.
Singapore prosecutors had said that Yeo "played a central role in many activities connected with the money-laundering case".
Local authorities have seized nearly $180 million in assets, with half linked to Low.