‘Don’t decide when you’re...’: JPMorgan CEO Jamie Dimon’s simple rule for better leadership 

In a world of high-stakes, rapid-fire decision-making, Jamie Dimon is offering a deceptively simple piece of advice: don’t make big decisions when you’re exhausted — especially not on a Friday.

The longtime chief of JPMorgan Chase says the lesson is one he has “learned and relearned” over decades on Wall Street. His reasoning is rooted in a universal workplace reality — by the end of the week, mental fatigue sets in, clouding judgment and increasing the risk of poor choices.

Hidden danger of ‘Friday fatigue’ 

Dimon’s warning comes from experience. After a long workweek, cognitive energy is depleted, making it harder to process complex information or weigh risks effectively.

“Making big decisions on a Friday when you're tired is a really bad idea,” Dimon said, underscoring how exhaustion can lead to rushed or flawed calls.

Experts echo this view, pointing to what psychologists call decision fatigue — a state where the quality of decisions deteriorates after prolonged mental effort. By Friday, both time pressure and fatigue combine to create a perfect storm for mistakes.

Lessons from four decades in finance 

Dimon’s perspective carries weight. With more than 40 years in banking — and nearly two decades at the helm of JPMorgan — he has navigated everything from financial crises to global economic shocks.

Yet, despite his experience, he admits he still occasionally falls into the same trap.

“I still make some of those mistakes,” he acknowledged, describing them as lessons that need constant reinforcement.

Beyond timing, Dimon also highlighted emotional discipline as a critical factor in leadership. Acting out of anger or stress, he noted, can be just as damaging as making decisions while tired.

Dimon’s advice goes beyond boardrooms. Whether in business, investing, or everyday life, the message is clear: timing and mental clarity matter as much as the decision itself.