I've got an over-sized concentration in VTG as well (over 10% of portfolio even at these levels), so the drop of ~25% in the last month has been painful (and ~30% since May).
My take is that this stock is illiquid and the price action yesterday IMO was tax selling (must have been someone that picked it up under $1 and wanted to push the capital gain into FY2020).
I can't see NIMA being a significant contributor to the bottom line at this stage (esp with retail consumption down), and I don't think we will have much visibility around the impact of the changed remuneration structure until Feb 2020.
VTG Price at posting:
$1.25 Sentiment: Hold Disclosure: Held