"Large organizations (such as banks, finance companies, insurance companies, labor union funds, mutual funds or unit trusts, pension funds) which have considerable cash reserves that need to be invested. Institutional investors are by far the biggest participants in securities trading and their share of stockmarket volumes have consistently grown over the years. For example, on a typical day, about 70 percent of the trading on the NYSE is on the behalf of institutional investors. Because they are considered knowledgeable and strong enough to safeguard their own interests, institutional investors are relatively less restricted by the security regulations designed to protect smaller investors."
( http://www.businessdictionary.com/definition/institutional-investors.html#ixzz3fPG8L9Z8 )
