When more than $88,000 was wrongly transferred to his bank account, his friends could not believe his luck and told him to pocket the windfall.
But Mr Jon Lim didn't think twice about returning it.
The 31-year-old was working late at home on the night of March 27, a Friday, when he received a text message from his bank saying that $88,593.31 had been credited to his account.
He initially thought the money could have been commission earned in his job as a financial adviser.
But he could not recall working on a deal that would generate such a large commission, so he started having doubts the money was meant for him.
The transaction turned out to be a Giro transfer from British-based medical equipment company Smith & Nephew, which has an office in Singapore.
As Mr Lim had no previous dealings with the company, it became clear to him that Smith & Nephew had committed an expensive mistake.
Though the money was more than half of what he makes in a year, he decided to return it to the company.
Mr Lim told The New Paper: "It was an immediate decision because it wasn't my money and it could have been important to someone else."
He did the right thing because anyone who keeps money that has been wrongly credited into a bank account is committing an offence.
Before Mr Lim found out where the money had come from, he was worried because of the large amount involved, said his sister, Ms Ezann Lim, 28.
"He actually called our parents' home to ask if any of us had transferred the money to him," she said.
"He has a baby daughter so his immediate reaction was: 'What if it belonged a mother who was paying for her child's hospital bills?' He would feel guilt-stricken if someone got into trouble or come into harm because of this."
Mr Lim said several friends and family members, including his wife, thought it might have been a money-laundering scam and advised him to leave the money in his account until the bank contacted him again.
His friends in the financial sector even came up with ways to keep the money, such as withdrawing it and then closing the bank account.
Miss Lim said: "They thought my brother was siao (Hokkien for crazy) to return it.
"If it had happened to me, I don't think I would have been so straightforward as to try to return the money the same day."
Ms Lim said the money would have meant a lot to her brother because he has a young child and had just moved to a new four-room flat that is only "minimally renovated".
But Mr Lim was never tempted to take what was not his, even when his attempts to return the money proved to be more difficult than he thought.
When he called the Smith & Nephew office that Friday night, it had closed for the day.
Nobody picked up the phone when he tried again the following Monday, Tuesday and Wednesday.
On Thursday, April 2, he finally got through to someone who confirmed there had been an error in the bank transfer.
Mr Lim said since he and Smith & Nephew use different banks, he could return the money only by cheque or a cashier's order. He had misplaced his cheque book and only managed to return the money via a cashier's order on April 16.
The next day, Smith & Nephew sent him an e-mail to acknowledge it had received the money. The brief e-mail read: "Hi Jon, We had (sic) received below fund (sic) yesterday. Thank you very much."
Mr Lim's friend, Mr Ang Wilin, 29, felt the company should have made a bigger gesture in appreciation of Mr Lim's honesty and efforts to return the money.
Mr Ang, who was shocked by the large amount involved, said: "I used to work in the banking sector and cases like this usually involve just a few hundred dollars.
"It was not Jon's mistake, but he went through so much trouble just to rectify it.
"There should have been a bigger gesture of appreciation from the company as it was no small sum."
A spokesman for the Singapore Kindness Movement commended Mr Lim's act, saying: "It was good of him to return the money and it speaks well of our society."
However, the spokesman said it was up to the company how it wished to show its appreciation since it had benefited from Mr Lim's act of kindness.
After three days of calling, TNP finally got through to Smith & Nephew's local office and spoke to the senior finance executive who had dealt with Mr Lim's case.
She said she did not know how the error occurred and declined to comment further.
Mr Lim said he has no hard feelings as it was only the right thing to do.
"I didn't expect anything in return," he said.