There are usually several systems involved in a settlement, all run by different parties - the bank (broker), the custodian (which holds the certificate) and th

There are usually several systems involved in a settlement, all run by different parties - the bank (broker), the custodian (which holds the certificate) and the counterparties that are trading. They all have representations of the same trade that are mostly out-of-sync, and reconciling these systems incurs delays. With the blockchain, none of these parties need necessarily trust each other, but all can share the same system which shows the current state of the transaction. All parties can observe a ledger that is distributed in real time. So they don't need any reconciliation steps anymore and all trades are "T0" (same day) settled