A stock market is a market for the trading of publicly held company stock and associated
financial instruments (including stock options, convertibles and stock index futures).
Many years ago, worldwide, buyers and sellers were individual investors and businessmen.
These days markets have generally become "institutionalized"; that is, buyers and
sellers are largely institutions whether pension funds, insurance companies, mutual
funds or banks. This rise of the institutional investor has brought growing professionalism
to all aspects of the markets.