Buyers of investment instruments or intermediated securities in the ordinary course of trading on a prescribed financial market (for example, the ASX) take free of a security interest1
Security interests over listed instruments or securities need to be appropriately controlled by a secured party to ensure they are not extinguished when the instruments or securities are sold. In fact, control should ensure the instruments or securities are not sold (at all) without the consent of the secured party.
See paragraphs 17.6.21 to 17.6.29 of Chapter 17 (Perfection) for how to perfect a security interest by control over investment instruments and intermediated securities.
Notes:
1 PPSA section 49 (link)