Many working hours in investment banks are spent on business trips, not to mention the concept of "working hours". It is normal for him to go on a business trip or come back in the morning and go to work in the company in the afternoon. Even if you don't travel, the work of investment banks is project-based. I will sleep in the office for a few days and nights when I have a project. When there is no project, I will slip away with a card in the morning and then slip away after work. Leaders usually just close their eyes. It's OK when the project is done.