via TMX Money - Canadian 30-year Government Bond Futures
According to regulatory changes in 2011, the no-down-tick rule was abolished, allowing any broker to sell any stock without owning it into the bid as long as the position was hedged.
Gold mining stocks, especially the junior stocks, had so seriously underperformed since that time, because they were heavily sold in the markets and government bond hedges bought. But short positions were merely reported as a negative number against the float.
So gold mining stocks, like GBN.V wound up having their stock so massively shorted that the entire publicly held float on the stock market was sold, in order to raise cash for hedging purposes. The fly in the ointment is that people are mostly holding on to their shares.
You can see how Canadian 30-year Government Bond Futures, which were listed prior to regulatory change had performed in 2011 once the no-down-tick rule was abolished:

source: http://tmx.quotemedia.com/futures-quote.php?qm_symbol=/LGB
A conclusion you reach is that regulatory changes were made to facilitate buying of government bond on already heavily encumbered gold mining shares.
-F6