noun
A professional who buys and sells stocks and other securities on behalf of clients. Used in financial contexts.
彼は大手証券会社のストックブローカーだ。
He is a stockbroker at a major securities firm.
証券アナリスト (securities analyst) analyzes stocks and provides recommendations, while ストックブローカー executes trades for clients.
Borrowed from English 'stockbroker'.