Dear Vijay,
Couldn't understand your question on site for traders. Even for the second part are you refering to trading large volumes on behalf of some company (if yes, then answer is no) or trading large volume on some company's stock (if yes, then what is your definition of large, if you can elaborate, maybe I can comment)
Regards,
definition on retail trade (As per my view of things and only example purpose)
1. portfolio size is small (less than one cr in indian market and 1 Lac $ in US mkt)
2. full beneficiary is trader himself (He dont share the profits anywhere, except may be some PMS fee etc)
As opposed to this, institutional trading is
1. portfolio size is large (100 cr in indian mkt, 10 M in US mkts)
2. Lot of dealers working on the porfolio building and maintenance
3. benefits are shared between the institution and individual traders
4. systems are run on the basis on risk mgmt systems.
5. traders are supported by tools and techniques of trading.
This is not an exclusive definition, but i hope it has given you some idea about what is in my mind.