From your link (click on link above the pie chart: "How to Use Pie chart"):
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.
It appears most of the "insitiutional" buyers are MM's. As Thomson states, "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."
This is not what is normally considered to be "institutional holdings".
I think that is enough DD from me on a stock that I have no intention of purchasing. Hope this helps.