Universities, banks, and hospitals are all institutions. Until you arrived at the bank, you'd forgotten that financial institutions were closed for the holiday. Thank goodness for the ATM! The noun institution also refers to a long held custom or practice in society. Even if your parents divorced when you were young, you might strongly believe in the institution of marriage. Or you might believe that once you enter the institution of marriage, your next stop will probably be a mental institution.
A consultant (from Latin: consultare to deliberate) is a professional who provides expert advice in a particular area such as security (electronic or physical), management, education, accountancy, law, human resources, marketing (and public relations), finance, engineering, science or any of many other specialized fields.
A broker is a professional who simply executes trades and investment transactions for a client. A broker may act on client requests, whether these are for simple stock purchases, option purchases, or more exotic investment transactions. A consultant does more than just help with transactions. The investment consultant is generally responsible for informing the client about any risks of a particular investment as opposed to the potential payouts. The consultant will help a client to compare the risks of diverse investment opportunities.