Follow the dollar.

Alice, a customer of Bank A, sends $1 to Bob, a customer of Bank B. Step through what each ledger records when the money goes by ordinary bank transfer, by stablecoin, and by a Fiat-on-Chain deposit token — a bank deposit in a form that can be sent at any hour. Watch where the dollar actually is at each moment, and who is owed what.

Step 1 of 5

Where the dollar is:

What each design asks the ledgers to do

	Bank transfer today	Stablecoin	Fiat-on-Chain deposit token
Ledgers that record the $1	3 — Bank A, central bank, Bank B	6 — Bank A, central bank, custodian bank, the issuer's books, the blockchain, Bank B (plus a monthly report and a data feed)	4 — Bank A, the shared settlement ledger, the central bank, Bank B; the shared ledger and the central bank read the same record
Entries booked before Bob has the dollar	10	30	15 as a token in Bob's hands; 20 if he moves it to his ordinary account
What Bob holds at the end	A deposit at Bank B	A coin that is an IOU from a private company, backed by a Treasury bill — until he cashes out	A deposit at Bank B, in a record format he can also send at 02:00 on a Sunday
Where the dollar is in transit	Money at the central bank, moving from Bank A's account to Bank B's	A Treasury bill owned by the issuer; the deposit left the banking system	Money at the central bank, moving from Bank A's account to Bank B's
Who Bob's credit risk is on	Bank B (insured)	The issuer and its custodian (uninsured)	Bank B (insured)
Finality	At the central bank, in business hours	On the blockchain for the coin; at the central bank again when Bob cashes out	Immediate and certain, in central bank money, 24/7
How the two records are kept equal	Statements compared at the end of the day	A monthly accountant's report; a data feed republishing it	Proven every minute: tokens in existence = bank ledger, or token creation stops by itself
A separate pool of money, a data feed, a bridge between blockchains	None needed	All three	None needed
Cross-border	Chains of correspondent banks: more ledgers, more days	The coin moves; the Treasury bill does not; a bridge if the blockchains differ	Two central banks' ledgers settle at the same instant — each side happens, or neither does

Amounts are illustrative. A "deposit" is money a bank owes its customer. "Money held at the central bank" is the bank's own account at the central bank, which the central bank's payment system (called the RTGS) moves between banks. The Bank for International Settlements (BIS) is not a ledger in any of the three; it writes the standards these designs are judged against, and scenario 3 follows its published concept of a shared ledger.