[smallblacksun]

I don't think it relates to the amount of money, but about gaining trust. People are more willing to trust someone with their money if they look professional, thus the tellers wearing suits and the fancy lobbies in banks. The traders don't need to gain anyone's trust, so there is no incentive. Similarly, the secretaries and PR people at the software company I work for wear suits, while the programmers wear jeans and a t-shirt.