Koon Yew Yin may not be a household name unless you’re an active investor in Malaysia. But within Malaysian investing circles, he was a titan.
He built his career as a civil engineer and went on to co-found three of Malaysia’s largest listed construction giants: Gamuda, IJM Corporation, and Mudajaya Group.
After retiring from the corporate world in 1983, he became a full-time value investor. He was famous for his high-conviction bets on “super-growth” stocks—notably glove makers and construction counters—and for openly sharing his portfolio and strategies on his blog and forums like i3investor.
His track record speaks for itself:
2013–2014: Bought into furniture makers like Latitude Tree (now Lii Hen), believing they would benefit from a strengthening USD. He entered around RM1–RM1.80. The stock surged to RM8 by 2015.
2015–2016: Identified VS Industry as a beneficiary of Dyson’s supply chain expansion in Malaysia. Became a top 30 shareholder. The stock appreciated more than 300%.
2019: Noticed oil & gas services company Dayang’s utilization rates were hitting 100%. The stock rallied from RM0.50 to RM2.
2020: During Covid, he recognized the surge in demand for medical gloves and went all-in—with leverage—on Supermax and Comfort Gloves. Supermax ran from RM0.70 to over RM10 within months. His portfolio grew from RM30 million to over RM100 million during this period.
Koon passed away on 3 February 2025 at the age of 93. But his legacy lives on. Here are 10 investment insights he left behind:
1. The “Golden Rule”: Profit Growth is King
“My golden rule is: share prices always follow earnings growth… Do not buy shares because they are cheap in terms of NTA or book value. You must buy shares because they are growing.”
— Source: Blog Post: “My Golden Rule for Share Selection”
Insight: The only thing that moves a share price sustainably is the growth of its earnings per share (EPS). If a company has high assets but flat earnings, the share price will stagnant.
2. Look Forward, Not Backward (Forward P/E)
“Investment is for the future. You should not look at the past… If you buy a share with P/E 10 and the company profit grows by 100% or doubles, the P/E will be reduced to 5. It is very cheap.”
— Source: Article: “Why I Buy Shares with High P/E Ratio”
Insight: A stock might look expensive today based on last year’s earnings. But if the profit doubles next year, the “Forward P/E” is low.
3. Be a “Shark” on Earnings Announcements
“When a company reports a sudden jump in profit, it is a buy signal… provided the profit growth is not due to a one-off gain like selling land. You must verify that the profit growth is from its core business.”
— Source: Book: “Invest Like Koon Yew Yin” (Chapter on Quarterly Reports)
Insight: The best time to buy is immediately after a company announces a quarterly result that beats market expectations.
4. Concentration Over Diversification
“Diversification is for idiots… If you have done your homework and you are sure of the profit growth, you should put all your eggs in one basket and watch the basket.”
— Source: Blog Post: “Concentration vs Diversification” (Quoting Warren Buffett/Andrew Carnegie)
Insight: Do not buy 20 stocks to feel safe. If you have done the research, buy your best idea heavily.
5. Sell When the Growth Story Ends
“I will sell as soon as I see the company reports two consecutive quarters of reduced profit… There are so many other good shares to buy. Why hold onto a loser?”
— Source: Article: “When to Sell”
Insight: He does not hold on to “losers.” He sells the moment the data changes.
6. Avoid “Laggards” (Don’t Catch a Falling Knife)
“Do not buy laggards. Do not catch a falling knife. A share price falls because of selling pressure. There are always more sellers than buyers for a losing stock.”
— Source: Article: “Why You Should Not Buy Laggards”
Insight: Never buy a stock just because it has dropped 50%. Stocks usually drop for a fundamental reason that insiders know before you do.
7. Management Integrity is Non-Negotiable
“You must check the track record of the major shareholders and management… If they have a history of cheating minority shareholders, stay away. A leopard never changes its spots.”
— Source: Open Letter: “Privatization of Public Listed Companies”
Insight: Governance matters. Poor management behaviour is rarely a one-off event.
8. Use Margin Financing (Aggressively)
If you are poor, you must use margin finance to get rich. If you are already rich, you use margin finance to get richer… But you must have a strict stop-loss rule.”
— Source: Article: “How to Use Margin Finance to Increase Profit”
Insight: This is controversial and high risk: If you are sure a stock is undervalued and growing, use borrowed money to amplify your returns.
9. Technical Analysis is for Timing Only
“Fundamental analysis is to select the stock and technical analysis is to time the entry and exit… A chart cannot tell you the future earnings of a company.”
— Source: Article: “Fundamental vs Technical Analysis”
Insight: Charts cannot predict earnings, but they can help with execution.
10. Patience (The Gestation Period)
“To be a successful investor, you must have patience. You must have the patience to hold the shares for the market to realize the true value of the shares.”
— Source: Charity Letter: “My Scholarship Fund”
Insight: After you buy, you must wait for the “market mechanism” to work. The price won’t jump the next day.
By now, you’ll have noticed that Koon was an aggressive, growth-oriented investor. While he made fortunes, his high-conviction, concentrated approach carries significant risk — and not every investor should invest this way. Don’t follow blindly.
But if you’re a growth investor, these insights offer timeless wisdom worth applying.
May he rest in peace.
