Blueballs is correct. 13 January UBS Securities Australia Ltd purchased 4.3m ordinary shares. This is the same amount of shares traded off market yesterday.
Refer to company announcement
http://www.cbio.com.au/releases/11.01.18%20Notice%20of%20initial%20substantial%20holder.pdf
They made $1,354,500 on a $946,000 investment over 3.5 months.