I flicked the IRD an email via my login on there website a couple years ago just to clarify what my position was.

They deemed I was "not in the business of trading' and my loss (it was a bad year lol) they advised "This is a capital loss and therefore not claimable, even if you purchased these with the intention to sell"
I've left it at that since then with the thought that if I made money it must be a capital gain and therefore not claimable even if I purchased these with the intention to sell.

They did ask if I traded over 50k worth of shares or if I owned more than 50k worth of shares so I guess that point there must be different rules.