Payments - Introduction / Learning brief
Hong Kong's CHATS: A Multi-Currency RTGS
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In simple terms / 01
What this means in plain language
The Clearing House Automated Transfer System (CHATS) is Hong Kong's high-value settlement system, unusual for running real-time settlement in four currencies side by side.
The Clearing House Automated Transfer System (CHATS) is Hong Kong's high-value payment system. It settles large payments one at a time, in full, the moment they are made — an arrangement called Real-Time Gross Settlement (RTGS). What makes CHATS distinctive is that it does not run just one currency: it operates separate but parallel RTGS systems for the Hong Kong dollar, the US dollar, the euro, and offshore renminbi, each with its own settlement institution holding the accounts. Because Asian business hours open long before Europe and North America, running US dollar and euro settlement in Hong Kong extends the daily window in which those currencies can move.
Complete lesson / 02
Understand the full idea, step by step
When it is 09:00 in Hong Kong, New York has not opened and Frankfurt is barely awake. Yet a bank in Hong Kong can settle a US dollar payment with finality, right then, without waiting for the American day to begin. How? Because Hong Kong runs real-time gross settlement not just for its own currency, but for several others — in parallel, in the same city.
CHATS at a glance
- Full name
- Clearing House Automated Transfer System
- What it is
- Hong Kong's high-value RTGS arrangement
- Oversight
- Hong Kong Monetary Authority (HKMA)
- Daily operation
- Hong Kong Interbank Clearing Limited (HKICL)
- Currencies settled
- Hong Kong dollar, US dollar, euro, offshore renminbi
- Distinctive feature
- Parallel single-currency RTGS systems plus payment-versus-payment links
Four systems, not one pot
The precise picture is worth getting right: CHATS is not one system with a four-currency account. It is four parallel RTGS systems, one per currency, each with its own settlement institution — the institution across whose books that currency's final entries are made. Hong Kong dollar payments settle across accounts at the HKMA. For the US dollar, the euro, and offshore renminbi, a designated commercial bank acts as the settlement institution for that currency, holding the participants' settlement accounts. A US dollar payment in CHATS never touches a Hong Kong dollar account; the systems run side by side, on the same operational rails, under the same oversight.
You may be wondering: how can US dollars settle in Hong Kong at all? Do dollars not live in America?
Ultimately, yes — the US dollar CHATS settlement institution holds its own dollar funding through accounts in the United States. But within CHATS, what settles is a claim on that settlement institution, moved between participants' accounts on its books in real time. For the participating banks the effect is the point: final, per-payment US dollar settlement during Asian business hours, hours before American systems open. The Asian trading day no longer has to wait for New York.
Payment-versus-payment (PvP) — the two currency legs of a trade settle only together, or not at all
PvP is a settlement discipline for foreign exchange: the system links the two legs so that Bank Alfa's dollars pay out only if Nordbank's Hong Kong dollars pay out in the same act. Neither party is ever exposed for the full principal of the trade. Because CHATS runs several currencies in the same place and time zone, it can offer PvP links between its own systems — something a single-currency RTGS can never do alone.
The FX trade settles PvP
- INSTRUCTION
Bank Alfa and Nordbank each instruct their leg: USD 10,000,000.00 from Bank Alfa to Nordbank in the US dollar system; the agreed HKD amount from Nordbank to Bank Alfa in the Hong Kong dollar system.
- VALIDATION
The two instructions are matched as one PvP pair — same trade, opposite directions, two currencies. An unmatched leg settles nothing.
- VALIDATION
Each system checks its sender is covered: Bank Alfa's US dollar settlement account and Nordbank's Hong Kong dollar settlement account must both hold the funds.
- SETTLEMENT
Both legs settle together — dollars move on the US dollar settlement institution's books at the same moment Hong Kong dollars move on the HKMA's books. One leg without the other is impossible by design.
- NOTIFICATION
Both banks are notified of a settled pair. Neither ever stood exposed for the principal.
COMMON CONFUSION
“CHATS lets a bank pay US dollars straight out of its Hong Kong dollar balance — one multi-currency account covers everything.”
Each currency is its own system with its own settlement institution and its own accounts. A bank that wants to send US dollar CHATS payments must hold and fund a US dollar settlement account; its Hong Kong dollar balance is invisible to the dollar system. "Multi-currency RTGS" means parallel systems under one roof — not one blended pot of money.
STRICTLY SPEAKING
Strictly speaking, which commercial bank serves as settlement institution for each non-HKD currency, which PvP links operate — including links to systems outside Hong Kong — and the operating hours of each system are designated arrangements that have changed over the years and can change again. The durable lesson is the architecture: parallel single-currency RTGS systems, each settling across a named institution's books, joined by PvP where trades span two of them.
FOR NOW, REMEMBER
- CHATS is Hong Kong's high-value RTGS arrangement — four parallel systems for HKD, USD, EUR, and offshore renminbi.
- Each currency has its own settlement institution: the HKMA for Hong Kong dollars, a designated commercial bank for each of the others.
- Settling US dollars and euros in an Asian time zone extends those currencies' daily windows by hours.
- PvP links settle both legs of an FX trade together or not at all, removing principal risk on the exchange.
TRY IT YOURSELF
Cassia Bank proposes to settle an FX trade with Nordbank in Hong Kong by sending its US dollar leg through CHATS at 09:30, with Nordbank promising to send the offshore renminbi leg by 11:00 the same morning. A colleague objects. What is the strongest objection?
One of CHATS's four currencies is offshore renminbi — which raises the bigger question of how renminbi payments cross borders at all. China built a dedicated rail for exactly that.
KEEP GOINGKey takeaways / 03
Three things to remember
- 01
CHATS is Hong Kong's Real-Time Gross Settlement (RTGS) system for high-value payments, overseen by the Hong Kong Monetary Authority (HKMA) and operated with Hong Kong Interbank Clearing Ltd (HKICL).
- 02
It runs four parallel currency systems — Hong Kong dollar, US dollar, euro, and offshore renminbi — each with its own settlement institution.
- 03
Settling US dollar and euro payments in an Asian time zone extends those currencies' operating hours and supports payment-versus-payment foreign-exchange settlement.
Practical use cases / 04
Where you would use this
A Hong Kong bank settles a large interbank Hong Kong dollar payment in real time and in full through CHATS.
Two banks settle a US-dollar-against-Hong-kong-dollar foreign-exchange trade on a payment-versus-payment basis, so neither currency leg pays out unless the other does.
A regional bank uses the offshore renminbi CHATS to settle a large yuan payment during Asian hours rather than waiting for onshore systems.
Worked example / 05
Put the idea into a real situation
Illustrative example: Harbour Bank in Hong Kong owes 5,000,000 US dollars to Delta Bank and is receiving 39,000,000 Hong Kong dollars in return under a foreign-exchange deal. Using the payment-versus-payment link between the US dollar and Hong Kong dollar CHATS systems, the two legs are held and released together: the US dollar leg only settles the instant the Hong Kong dollar leg does, so neither bank is left having paid without receiving.
Operational sequence / 06
Follow the message and decision path
This compact sequence is a learning model. Exact routing and rulebook behavior can vary by scheme, participant, and implementation.
Read the steps as text
- 01MessageBank Alfa submits the payment to CHATSBank Alfa (paying bank) → CHATS / HKICL · CHATS payment instruction
Bank Alfa sends the payment instruction into HKD CHATS, the Hong Kong dollar real-time gross settlement system. CHATS also clears USD, RMB, and EUR, but this payment runs on the HKD system. Nothing has moved yet — it is a message.
- 02ProcessingCHATS checks the settlement-account balanceCHATS / HKICL
CHATS reads whether Bank Alfa's settlement account at the HKMA holds enough to cover HKD 8,000,000.00. An RTGS payment settles immediately only when there is sufficient balance to settle it.
- 03SettlementThe HKMA settles the payment individuallyBank Alfa (paying bank) → Nordbank (receiving bank)
On the HKMA's book the payment settles individually and on a gross basis — Bank Alfa's settlement account is debited and Nordbank's is credited, one payment at a time, in central-bank money. Settlement is immediate.
- DR Bank Alfa's settlement account at the HKMA — HKD 8,000,000.00
- CR Nordbank's settlement account at the HKMA — HKD 8,000,000.00
- 04MessageNordbank is confirmed of the settled paymentCHATS / HKICL → Nordbank (receiving bank) · CHATS settlement confirmation
CHATS tells Nordbank the funds are on its settlement account and settled, with the details of whom to pay. This is information, not the money itself.
- 05PostingNordbank books the fundsNordbank (receiving bank)
Because the interbank leg already settled with finality across the settlement accounts, Nordbank can book the funds to its customer without waiting for anything else.
- CR Beneficiary's account at Nordbank — HKD 8,000,000.00
Read the steps as text
- 01MessageRiya pays using Arjun's mobile numberRiya (payer) → Bank Alfa (sending bank) · FPS payment instruction
Riya asks Bank Alfa to send HKD 600.00 to Arjun using his mobile number or FPS ID — a proxy address. She never has to know or type his account number, and FPS runs around the clock, so this works at night.
- 02MessageFPS resolves the proxy to Arjun's accountBank Alfa (sending bank) → FPS / HKICL · FPS addressing lookup
The Faster Payment System looks up the mobile number or FPS ID in its addressing directory and finds it points to Arjun's account at Nordbank. Only the mapping travels here — this message carries no money.
- 03PostingBank Alfa debits RiyaBank Alfa (sending bank)
Now that the destination is known, Bank Alfa books a debit against Riya's account on its own ledger for the amount she is sending.
- DR Riya's account at Bank Alfa — HKD 600.00
- 04PostingNordbank credits Arjun almost immediatelyNordbank (receiving bank) → Arjun (payee)
The payment routes through FPS to Nordbank, which credits Arjun's account almost at once. Arjun can spend the money straight away — he does not have to wait for the banks to settle between themselves.
- CR Arjun's account at Nordbank — HKD 600.00
- 05SettlementThe interbank leg settles on the HKMA bookHKMA / CHATS (settlement) → Nordbank (receiving bank)
Arjun already has the money, but the two banks still owe each other. HKD FPS is designated as part of HKD CHATS, so the interbank amount settles in central bank money on the HKMA settlement book.
FPS settlement rides on the CHATS / HKMA book: the HKMA provides the settlement book for HKD FPS, which is designated as part of HKD CHATS.
- DR Bank Alfa position on the HKMA book — HKD 600.00
- CR Nordbank position on the HKMA book — HKD 600.00
Evidence & review / 07
Evidence & review
CHATS, Hong Kong SAR — HKD, USD, EUR, and offshore RMB RTGS arrangements
What this brief simplifies: Settlement institutions for non-HKD currencies are described by role, not named, because designations are operator-specific and change; PvP matching is shown as a single clean pairing without the systems' internal queue and optimisation detail.
Sources for this brief2
- Market practiceMarch 2003 edition
A glossary of terms used in payments and settlement systems ↗ — CPSS (now CPMI), Bank for International Settlements · Payment versus payment, settlement institution
Terminology has evolved since this edition; newer CPMI publications refine some definitions.
- Simplified educational illustration
Payments Signal editorial teaching models — Payments Signal
Used wherever diagrams, scenarios, figures, or example values are didactic constructions rather than sourced facts; every such use carries a simplifications disclosure. All people, companies, banks, and list entries in examples are fictional.