He was a 19-year-old full-time national serviceman when he and his businessman father opened a joint investment account at a private bank in July 2006.
Two years later, Mr Ian Ow Tuc Yun used the account to trade in futures and racked up losses of close to $900,000 in a space of nine months.
Now, the 26-year-old student and his father Ow Weng Fye, 63, are seeking $2.6 million in damages from the Singapore branch of Credit Suisse, in a lawsuit that opened for hearing yesterday in the High Court.
They assert that their relationship manager Aaron Chwee Toh Yee - named as the second defendant in the suit - had misled and manipulated the naive son into making the trades, while keeping the father in the dark.
The Ows, represented by Mr Adrian Tan, want the trades made by the son to be voided on the grounds that he was a minor at the time.
While their trading losses amounted to some $900,000, the Ows contend that the money would have grown to $2.6 million had it been invested according to the father's instructions.
Credit Suisse, represented by Senior Counsel Alvin Yeo, said that although instructions for the trades were given by the son, the bank's telephone transcripts showed that the father was consulted and kept in the loop.
The bank argued that the joint account was governed by Swiss law, where the age of majority is 18, so the son was not a minor when he opened the account.
Even if Singapore law applies, the bulk of the loss-making trades were made by the son after he turned 21 on May 25, 2008, the bank contended. And in any case, the father remains liable for the trades as the joint account holder.
The bank does not accept the Ows' calculation of their losses. It puts the loss at about $500,000 and calls the damages sought "wildly speculative".
The older Ow, who is now retired, was the executive director of a stockbroking firm and later ran a garment business.
The younger Ow, who finished a diploma course in commerce this year, is waiting to start a degree course in management and accounts.
Mr Ian Ow was a junior college student when he met Mr Chwee, the older brother of a friend.
Taking the stand yesterday, he told the court that in 2006, Mr Chwee persuaded him to open an online trading account and said he would show him the ropes.
Mr Ian Ow said he borrowed $10,000 from a friend to trade until the funds were depleted.
In May 2006, he introduced Mr Chwee to his father.
Two months later, the Ows signed agreements to open accounts with Clariden Leu, a Swiss private bank that later merged with Credit Suisse.
The elder Mr Ow put assets of about $1 million into the account, including shares worth $660,000.
During the financial crisis at the end of 2007, the businessman told Mr Chwee that he wanted the shares to be sold, held in cash, and then re-invested in Asian equities in 2009.
The Ows now claim that Mr Chwee had influenced the son to trade with the money by claiming that Clariden had systems that could pinpoint profitable trades.