CHESS (Clearing House Electronic Sub-register) is ASX’s share transaction and settlement system. A unique Holder Identification Number (HIN) is allocated to anyone with CHESS-sponsored shares.
Custody means when trading ASX Stocks, ETFs, ETCs and Bonds with Saxo Markets (Australia) Limited in a custody share trading account, Saxo Bank A/S is acting as the custodian of the assets. These assets are held on your behalf by Saxo Bank’s sub-custodian Citibank, under Saxo Markets (Australia) Limited.
See the full comparison on CHESS/HIN and Custody here.