Institutional ownership and PPS movement are not strongly correlated. Institutions trade like individuals, though usually with greater volume. When there is basically no demand for a stock, that is either buy or sell demand (few are looking to change their position) then the MM can move the PPS at will to try to make demand, and/or change their own position. When the demand returns, e.g. news, more people wish to change their position and the MM is less in control and that is where the risk resides for the MM.
FFTT
JBAIN