Jamie Dimon shared the one characteristic he says sinks CEOs

• Jamie Dimon warned on a podcast that insecurity, not arrogance, is a leader's biggest enemy.
• He says he leaves every board meeting so the board can meet without him.
• Humility is a characteristic he looks for when promoting people.

Jamie Dimon has watched executives rise and fall for decades. The trait that sinks them, he says, isn't the one you'd guess.

The JPMorgan boss says it isn't arrogance that ruins leaders, it's insecurity. And the warning signs are flattery, friendly hires, and glossy PowerPoints.

"When some people get a big job, some grow into it, and some swell into it," the JPMorgan Chase CEO said on "The Master Investor Podcast with Wilfred Frost."

What drives the swelling, in his view, is insecurity.

Dimon, 70, has run JPMorgan since January 2006, steering it through the financial crisis, COVID, and the 2023 banking turmoil, and building it into the world's largest bank, with a market value of around $900 billion. He knows the pressures of a big job firsthand.

The problem is structural, Dimon explained: every promotion shrinks the share of the job you actually understand. He imagined a star mortgage trader who was suddenly promoted to run all of a bank's trading.

"Now he's got equities, commodities, fixed income, Asia," he said. "He's an expert in mortgages, but not in the other ones." One more step up and 36 functions report to him. "It induces insecurity."

How leaders respond to that feeling is the fork in the road. The secure ones, Dimon said, have "these innate skills to trust people, to get the best out of people, to not get embarrassed by not knowing."

The insecure ones build a bubble. "It becomes friends of Bob. It becomes PowerPoints: make them look good, don't tell them the bad news. And that is what causes the problem," he said. "You get that in governments too, where leaders are surrounded by people telling them what they want to hear, because they're insecure."

From there, he said, reality starts to disappear: "Reports start being modified to look good, as opposed to undressing what's going on in your company."

A secure leader treats criticism as a good thing, Dimon said. "You're not going to hurt my feelings by telling me we have a crappy product," he told Frost. "Customer complaints are a gift."

He watches for the tells in his own ranks, "I have seen people in my own management teams who were twisting in their chairs" while junior staff described problems, he said. "That tells me something about the manager. They probably shouldn't have that kind of job."

Dimon said he has built his own safeguards. He said that for 20 years, he has left every JPMorgan board meeting so directors can talk without him, "I insisted upon it," and when executives disagree with him, he has them argue their case to the board directly.

Humility runs through his broader hiring philosophy, too. His character test for big promotions: "Would you promote someone to a big job that you wouldn't have your child report to?" And recognizing others' work, he added, is "a form of humility ... It's saying it wasn't me, it was you."

His advice for the ambitious follows the same thread: stay curious, and never assume you've made it. The scourge of any company, he said, is "bureaucracy, complacency, and his cousin, arrogance."