ifitlooks, here's some info from the Thomson site about how to use the pie chart (which includes their definition of "institutional" and advises comparing with the days data to the month): So while we can't say how much of the 11% is institutional ie on behalf of an institution/ie fund/other, we can see that it is unusual activity compared to the 30 day average of just 3%.
How to Use Pie Chart
The I-Watch Total Trade Volume pie charts allow users to determine whether Institutional or Retail investors are driving today's price movement for this stock.
After a broker/dealer executes a trade, it often reports the trade to Thomson's proprietary communications network. The Total Trade Volume Chart segments each trade as either Institutional or Retail, based on the broker reporting the trade.
Institutional - a trade reported by a major brokerage firm which typically trades on behalf of major mutual funds/portfolio managers. While these firms also have retail branches, the amount of trades reported on behalf of institutional investors dwarfs the limited amount of retail trades that are reported.
Additionally, Institutional brokers often maintain internal house trading accounts as "market makers." When these firms report their trades it is impossible to determine whether the trades were executed on behalf of an institutional client or for the firm's own house trading accounts. While trading patterns for institutional clients and house accounts tend to differ, the fact that "Big Money" is behind the trades means that these investors/traders have the ability to move markets.
Retail - a trade reported by a broker that primarily executes on behalf of retail investors, such as Charles Schwab's Mayer Schweitzer.
Non I-Watch - this portion of the chart refers to trades not reported over Thomson's proprietary communications network. Broker participation is voluntary, so it is rare that all trading volume is accounted for. These trades can be related to either institutional or retail trading.
Compare today's activity to prior 30-day average - this comparison lets you know if today's activity, specifically the breakdown between Institutional and Retail, is "unusual" relative to the rolling 30-day average.