SINGAPORE, March 18 — Singapore’s apex court has dismissed appeals by John Soh Chee Wen and Quah Su-Ling for reduced sentences, upholding their jail terms over their roles in the country’s largest securities fraud involving the manipulation of three penny stocks.

The Court of Appeal affirmed the original sentences of 36 years’ imprisonment for Soh and 20 years for Quah, ruling that the penalties were justified given the scale, sophistication and market impact of their offences, The Edge Singapore reported.

“In terms of the first appellant’s aggregate sentence, we do not think the sentence of 36 years imprisonment can be said to be manifestly excessive,” Chief Justice Sundaresh Menon was quoted as saying.

“He caused very significant harm to the market and its stakeholders. In doing so, he had also severely harmed Singapore’s reputation as a financial hub.”

The three-judge bench, which included Justices Tay Yong Kwang and Andrew Phang, reviewed whether the sentences imposed by High Court Judge Hoo Sheau Peng should be revised but ultimately found no basis to alter them.

The case centred on an elaborate scheme between August 2012 and October 2013 involving 189 accounts across 20 financial institutions, which were misled into financing coordinated trades that artificially inflated shares of Blumont Group, Asiasons Capital and Liongold Corp.

According to The Edge Singapore, the manipulation ended with a market crash on October 4, 2013 that wiped out more than S$8 billion in value, marking one of Singapore’s most significant financial scandals.

Menon rejected Quah’s defence that she played a minor role, stating it was inaccurate to characterise her as merely assisting Soh and that her culpability was not lower in all respects.

The court, however, declined the prosecution’s request to enhance Quah’s sentence over allegations made by her lawyer against the trial judge, citing fairness as the claims were made without her instructions.

Both defendants were convicted of offences including false trading, price manipulation, deception and cheating, with Soh also found guilty of witness tampering, bringing to a close a long-running legal saga.