Wear what you want. He sounds like an inexperienced CEO who is compensating by trying to shame you into dressing like he does. Unless you're wearing a tuxedo

Wear what you want. He sounds like an inexperienced CEO who is compensating by trying to shame you into dressing like he does. Unless you're wearing a tuxedo, it's pretty hard to over-dress at work. Be comfortable with what you're wearing, and be confident. If he brings it up again just say "This is how I like to dress" and leave it at that. If he continues to press, ask him if there is an over-dressing policy at work. Don't let him bully you because of his title.