Ann: December 2016 Quarterly Activities Report, page-19

"Does this mean Blackrock is taking physical gold from NST?"

I highly doubt it as the company can not sell Blackrock its own shares as it doesn't own shares in itself. Blackrock would have to buy the shares from a third party holder of NST shares to make a purchase or sell to a third party to make a sale.

Now in principle an in species transaction can involve a physical asset like gold or anything else for that matter or a financial asset that is not cash, ie other types of securities, bonds etc.

Maybe Blackrock just swapped shares in another company for shares in NST or visa versa in these transactions. That's just my best guess. Esh