“One of the strangest things about Dimon’s career is that the man who now leads the world’s largest bank has never really worked for a bank. He helped Weill buy and transform financial-services companies. And then he ran banks. During his years with Weill, there was a clear division of labor: Weill was chutzpah and vision, Dimon was operations and numbers. He would obsess over downside, integration, and costs, cutting newspaper subscriptions and country-club memberships and jobs. Everyone noticed how good he was, and by 1998, Weill, a complicatedly insecure egotist, could no longer tolerate it. He fired his professional son. Dimon considered CEO jobs at Home Depot and elsewhere and then shocked everyone by agreeing in 2000 to run a hodgepodge of poorly integrated midwestern banks, which overcompensated by calling itself Bank One. In four years in Chicago, Dimon relentlessly fixed the institution”
https://nymag.com/intelligencer/article/jp-morgan-chase-jamie-dimon-biggest-big-bank.html