The answer to my question :

"How can we explain the fact that institutions are not investing in the 10-15% range as opposed to the actual 2%?

Are they seeing risks we do not see? Are they waiting for a more stable momentum in the share price? "

ended up to be that an institution will not typicaly  invest 10% in a single company. ... Well, in my question the 2% is for the total of the 45 institutions (it is a fact that is published), so the 10% is also for the total of the 45 institutions in that question. 

To make my question more clear, the majority of the institutions have invested small amounts. Why is this ? Without an answer on this, my opinion is that for now PYR is more on the watchlist of the institutions than it is in their portfolio. Not enough revenues ?

Peter said there is more and more institutions that do invest. This is a very good news. The next good news yet to come is when they will start buying shares like institutions do, i.e. large volume.