A team of junior bankers had been regularly working until 4 a.m. for weeks when they were called together for a pizza party last year.

Some of the young analysts and associates assumed it was a reward for their work pitching and closing deals on the industrials team at Robert W. Baird, a Midwestern bank founded more than a century ago. Instead, the managers who organized the gathering in Chicago told the group they needed to step up their performance, according to multiple people familiar with the meeting.