I'd agree it has to do with a delisting - but with all due respect to the TSX - the institutional exodus shows strong evidence that is was caused by the delisting actions of the NYSE/AMEX.

The date the company filed their notification of failing to meet NYSE/AMEX listing requirements, and the date of high volume appears to confirm this.

Institutions do have guidelines, and those guidelines we often hear about are by those institutions that openly disclose their moves by filing 13G/A. Guidelines with hedge funds are constantly amended depending on the circumstances. Two major holders, Tradewinds and Greywolf, are hedge funds and played this beyond where the institutions had long bailed.