I find the shorts quite fascinating. The two major spikes have...

I find the shorts quite fascinating. The two major spikes have nearly the exact same volume and price.   You'd have to say they involve the same parcel.   

If all outstanding positions are meant to be reported back to ASIC each day, then this could simply be a case of late/missed reports.  Does anyone know how it actually works?  

Another thought is the spikes represent transfers between parties.  As the trades involve the short position and not the physical stock, I doubt they would need to be included in the day's trading volume.

Based on Shortman's 3 year chart, I'm also guessing they're the ones purchased between Oct'14 and Jun'15 for between $6 and $8, making them currently worth around $150M+ profit.   For all we know, the holder may have already purchased an equivalent offset and is keeping them purely for tax reasons.  

http://www.shortman.com.au/stock?q=SGH

I apologise if this has already been discussed.   SGH has an impressive post count and I've by no means read them all.