PI is the big buyer of CHX too and seems they like SGN too. They were early into CHX so maybe this is a sign of times to come. Good fundamentals just like CHX so its not hard to see SGN is a buy at this price.
I wouldn't doubt Hesperian moving from one fund to another. It took a couple of days last time but did come out on Canadian Insider. They deal mostly through PI so thats probably who it is.