Thinking of investing? JPMorgan CEO Jamie Dimon says this simple childhood exercise shaped his success

Jamie Dimon, the CEO of JPMorgan Chase, has revealed that his journey in finance began long before business school or Wall Street. As a child, Dimon learned how to value businesses through investment simulation exercises designed by his father, a stockbroker, an experience he says shaped the disciplined approach that later helped him build America's biggest bank.

Speaking on The Master Investor Podcast with Wilfred Frost, Dimon recalled spending hours studying industries, annual reports and company histories before deciding what a stock was worth.

“He would give me an industry you might know something about, like a restaurant,” Dimon said. “And say, ‘Okay, look at this. Look at the history. Read the annual report. Study the industry if you want. What would you pay for the stock?”

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Learning stock picking from his father

Those exercises became the foundation of Dimon's investing philosophy. While his father, Theodore Dimon, encouraged all three sons to learn about the stock market, Jamie was the only one who fully embraced the lessons.

“It is brutally hard,” Dimon said. “Then you learn the ‘why.’”

His interest in finance extended beyond the stock market. By high school, Dimon spent his free time reading books and papers on psychology, economics and accounting.

“I read Graham and Dodd in high school—I was a nerd,” Dimon said. “I read all of Freud’s books. I always would be taking this stuff in.”

Dimon bought his first stock at the age of 14 in 1970 with guidance from his father. He later graduated from Tufts University before earning an MBA from Harvard Business School.

From Wall Street apprentice to JPMorgan CEO

After graduating, Dimon joined American Express in 1982 as an assistant to then-president Sanford "Sandy" Weill. Reflecting on his early career, Dimon recalled the mindset that guided him.

“My first goal was to learn something and not say anything until I could add some value,” a 28-year-old Dimon told Fortune in a 1984 profile.

Working under Weill proved to be a defining chapter in his career. When the pair left American Express to lead consumer lender Commercial Credit in 1986, Dimon became chief financial officer at just 30. The experience laid the groundwork for senior leadership roles at Citigroup and Bank One, which merged with JPMorgan Chase in 2004. Two years later, in 2006, Dimon took over as CEO of JPMorgan Chase.

Building America's largest bank

Today, Dimon is among the few Wall Street chief executives who have remained in charge since the 2008 global financial crisis. Under his leadership, JPMorgan Chase has become the largest bank in the United States. The company ranks No. 12 on the Fortune 500 and No. 19 on the Global 500 list.

According to JPMorgan's 2025 annual report, the bank generated $185.6 billion in revenue in 2025, up by $5 billion from the previous year. Dimon's personal net worth is estimated at $3.2 billion, according to the Bloomberg Billionaires Index.

Why Dimon says success is about discipline, not ambition

Despite leading a bank now valued at close to $1 trillion in market capitalisation, Dimon said becoming the biggest was never his goal.

“No.”

Instead, he said his approach has always been centred on discipline and continuous improvement rather than chasing size or status.

“I think you get in trouble if you say, ‘I want to be the biggest bank in the world,’” Dimon said, pointing to NFL legends Tom Brady and Peyton Manning. “They say they didn’t have the best arm and they weren’t good runners, but they became the best.”

Dimon has expressed the same philosophy before. Speaking at the Fortune Most Powerful Women Summit in 2025, he said success comes from giving maximum effort every day, even when every attempt does not produce the desired result.

“You can’t hit a home run every time you’re at the bat,” Dimon told Fortune Editor-in-Chief Allyson Shontell. “You keep working, stay humble, and work hard.”

For Dimon, the lesson remains the same as the one his father taught him decades ago: put in the work and understand the "why" behind every decision.