Ann: 2018 Half Year Results & Appendix 4D, page-11

Regarding the derivatives on the balance sheet. The notes say:
"Sequoia has an obligation to its clients to pay the value of the investment at expiry or when an unwind event occurs. The current asset amount and the non-current asset amount equals that of the investment obligation described as a current liability and a non-current liability. The carrying amount equals the amount of the investment obligation. The rise or fall offset each other"

Can anyone clarify what these derivatives are? And when do their expire/trigger?
I understand the asset/liability net each other off, but trying to get to more detail here, to assess whether it is a risk or not.