Stockbroker

Noun

 * 1)  A person who buys and sells shares (stock) on a stock exchange on behalf of clients.  May also provide investment advice and/or company information, depending on the level of service offered (or chosen by the client).

Thesaurus
Realtor, Wall Streeter, bill broker, bond crowd, broker, cambist, cotton broker, curb broker, dealer, diamond broker, discount broker, estate agent, floor broker, floor trader, floorman, furniture broker, grain broker, hotel broker, insurance broker, jobber, land broker, money broker, money changer, mortgage broker, note broker, odd-lot dealer, pawnbroker, pit man, real estate agent, real estate broker, registered representative, sharebroker, ship broker, specialist, stock dealer, stock-exchange broker, stockjobber, two-dollar broker

Etymology
stock + broker