Warren Buffett was just 11 when he made this investing mistake: ‘I decided from there on…’

Billionaire Warren Buffett is known to be one of the world's most successful and renowned investors who began investing since a very young age. Also known as Oracle of Omaha, he was just 11, when he first bought his stocks. The experience taught him a lesson about investing that stayed with him. Later in an interview, the investor recalled a mistake he made when he was young that shaped his future investment decisions.

Warren Buffett bought his first stock at 11, but sold it too soon

In an interview published by the CFA Research and Policy Center, Buffett recalled buying three shares for US$38 each when he was 11 years old. His older sister also purchased three shares of the same stock. However, the investment initially moved against them, with the share price falling to US$27. Buffett remembered that this happened in June 1942, when the Dow Jones Industrial Average stock market index tracking stood at 92.

As the siblings walked to school each day, his sister kept reminding him of the latest stock price. Eventually, when the shares recovered to US$40, both decided to sell, making a profit of US$5 each. But the story did not end there. Buffett recalled that the stock subsequently climbed to around US$212 per share, far above the price at which he had sold.


The experience left a lasting impression on the young investor. As he recalled in the interview, “I was tired of hearing about it,” referring to his sister’s repeated updates about the stock price. He eventually decided to keep his investment decisions to himself and think independently. “So, I decided from there on not to talk to anybody about what I did and just think by myself,” Buffett said.

The book that changed Warren Buffett’s investing approach at 19

Although Buffett had developed an interest in the stock market during childhood, he credited Benjamin Graham’s The Intelligent Investor with transforming his understanding of investing. “I’d been interested in stocks since I was 7 or 8 years old,” Buffett said in the interview. He had calculated his own averages and read every investment book available in his local library. Despite his enthusiasm, he felt he was not making meaningful progress.

That changed when he read Graham’s book at 19. Buffett said the lessons he learned from Graham became the foundation of his investing philosophy. “I got three ideas out of Ben’s book that have been the cornerstone of everything I’ve done,” he explained.

The first was to treat stocks as ownership in actual businesses rather than simply prices that move up and down. The second was Graham’s concept of Mr. Market, which Buffett said helped him develop the right attitude towards market fluctuations. The third lesson he learned was the principle of a margin of safety. Together, these three lessons shaped his investments and how he responded to changing market conditions.

Warren Buffett’s journey from a young stock investor to a billionaire

Known as the Oracle of Omaha, Buffett became one of the most successful investors in history. He served as chairman and chief executive of Berkshire Hathaway, the conglomerate with interests in dozens of businesses, including insurer Geico, battery maker Duracell and restaurant chain Dairy Queen. He retired as CEO at the end of 2025 and became chairman emeritus.

Buffett’s interest in money began early. The son of a US congressman, he bought his first stock at 11 and filed his first tax return at 13.

According to Forbes, his net worth stands at US$146.6 billion. Yet, one of the formative experiences behind his investing philosophy dates back to that first stock purchase, when a small profit and a subsequent price rally taught him to think independently about his investment decisions.