A man stands speaking to a crowd of sitting people, all wearing business attire.
A stock broker is speaking at a Wall Street conference.
People wearing business suits aren't necessarily stock brokers. A man talking to an audience doesn't imply it is a Wall Street conference.
The man might not necessarily be a stock broker, and he might not be speaking at a Wall Street conference.
There are plenty other professions where you are requiered to wear a suit other than being a stock broker.