Clearing — Payment Netting & Interbank Settlement Preparation

Clearing is the process of reconciling and netting payment obligations between financial institutions before final settlement occurs. It sits between a payment being authorised and money actually moving between bank accounts at the central bank.

Key distinction: Clearing = calculating who owes whom. Settlement = the actual money movement.

Clearing & Settlement Architecture & Multilateral Netting Calculator

Deferred Net Settlement (DNS) Mechanics

Payments are queued and batched during settlement windows. The Clearing House nets all bilateral obligations multilaterally, requiring central bank money (ESA) transfers only for the net residual difference at cut-off times.

INTERBANK BILATERAL PAYMENTSGROSS TOTAL: $2300k

Bank A ➔ Bank B ($)

Bank B ➔ Bank A ($)

Bank A ➔ Bank C ($)

Bank C ➔ Bank A ($)

Bank B ➔ Bank C ($)

MULTILATERAL NET SETTLEMENT RESULTS

Bank A Net Position- $600,000 (PAYER)

Bank B Net Position+ $300,000 (RECEIVER)

Bank C Net Position+ $300,000 (RECEIVER)

Gross Transfers Required (RTGS): 5 transfersNet Settlements Required (DNS): 3 transfers

Liquidity Saving Efficiency: 74% Liquidity Conserved

Why Clearing Exists

If every payment triggered an immediate bilateral transfer of central bank money, the system would be impossibly inefficient:

Bank A sends 10,000 payments to Bank B
Bank B sends 9,800 payments to Bank A
Without clearing: 19,800 gross transfers
With clearing: 1 net transfer of the residual difference

Clearing nets these obligations down to a single net position per bank per settlement cycle.

DNS vs RTGS — The Two Clearing Models

Deferred Net Settlement (DNS)

Attribute	Detail
How it works	All payments are batched; obligations are netted at end of a cycle
Settlement frequency	Once or several times per day (e.g. BECS: 3 settlement windows)
Liquidity requirement	Only net positions need to be funded
Risk	If a participant fails before settlement, all obligations unwind — systemic risk
Cost	Low — efficient use of liquidity
Examples	BECS Direct Entry, BPAY, VISA/Mastercard daily nets

Real-Time Gross Settlement (RTGS)

Attribute	Detail
How it works	Each payment is settled individually, in real time
Settlement frequency	Continuous, payment by payment
Liquidity requirement	Full face value must be available at time of instruction
Risk	Very low — each payment is final on settlement
Cost	Higher liquidity cost
Examples	NPP (via FSS), RTGS/HVCS (RITS), SWIFT (via correspondent nostros)

Australian Clearing Systems

BECS (Bulk Electronic Clearing System)

Operated by AusPayNet, BECS handles bulk batch payments:

Detail	Value
Payment types	Direct Entry credits, direct debits
File format	120-character fixed-width DE file
Timing	D+0 submission, D+1 value (next business day)
Settlement windows	3 per day via RBA RTGS
Scheme rules	AusPayNet BECS Procedures
Participants	ADIs (banks, credit unions, building societies)

BECS Clearing Cycle

Originator (batch file)
     │
     ▼ Submit DE file before cut-off
Originating ADI
     │
     ▼ Send file to Clearing House (AusPayNet/BECS)
BECS Clearing House
     │
     ├─► Net obligations calculated per ADI pair
     │
     ▼ Settlement instructions sent to RBA
RBA RTGS / ESA
     │
     ▼ Net positions settled
Receiving ADIs
     │
     ▼ Credit entries posted to customer accounts

BPAY Clearing

Operated by BPAY Group
Payments submitted via participating financial institutions
Batched and netted daily
Settlement via RITS/RBA

NPP Fast Settlement Service (FSS)

Operated by NPPA via RBA FSS
RTGS-based: each NPP payment settles individually and immediately
No netting — each instruction is final
Available 24/7/365

HVCS / RITS (High-Value Clearing System)

Operated by RBA via RITS (Reserve Bank Information and Transfer System)
High-value and time-critical domestic AUD payments
RTGS — payment by payment
Typically used for large corporate/treasury payments (>$250K rule of thumb)

Multilateral Netting — How it Works

In DNS clearing, all banks' positions are netted multilaterally:

Bank A → Bank B: $1,000,000
Bank B → Bank A: $600,000
Bank A → Bank C: $400,000
Bank C → Bank A: $200,000
Bank B → Bank C: $100,000

After multilateral netting:
  Bank A: net position = -$1,000,000 - $400,000 + $600,000 + $200,000 = -$600,000 (net PAYER)
  Bank B: net position = +$1,000,000 - $600,000 - $100,000 = +$300,000 (net RECEIVER)
  Bank C: net position = +$400,000 - $200,000 + $100,000 = +$300,000 (net RECEIVER)

Total net transfers: 3 (instead of 5 gross)

Intraday Liquidity Implications

Clearing models directly drive liquidity strategy:

DNS Liquidity

Banks must fund their end-of-cycle net position only
Intraday liquidity can be recycled — received payments can fund outgoing obligations
Risk: if inflows don't arrive before cut-off, bank must draw on credit facility or ESA

RTGS Liquidity

Each payment consumes full face value from the ESA immediately
Bank must prefund or actively manage ESA throughout the day
RITS provides intraday repo (collateral against RBA) to manage peaks

Gridlock Resolution

In RTGS systems, gridlock can occur when multiple banks are simultaneously waiting for inbound funds before they can settle outbound payments — a circular dependency.

RITS uses SWIFT's LSM (Liquidity Saving Mechanism):

Payments queue in RITS
LSM runs bilateral and multilateral offset algorithms
Circular dependencies are detected and resolved by simulating simultaneous settlement
Only residual net positions require actual liquidity

Clearing vs Settlement Summary

Stage	Clearing	Settlement
When	During payment processing	End of cycle (DNS) or immediately (RTGS)
What happens	Obligations calculated and netted	Central bank money transfers between ESAs
Who does it	Clearing houses (AusPayNet, NPPA, BPAY)	RBA (RITS/FSS)
Reversibility	Positions can still change	Final and irrevocable
Risk	Systemic (DNS only)	Eliminated at settlement

Clearing Cut-Off Times (BECS — Indicative)

Window	Submission Deadline	Settlement Time
Morning	Prior evening/night file	8:30 AM
Afternoon	Mid-morning	1:30 PM
Evening	Afternoon	6:00 PM

Exact times set by AusPayNet and subject to change. Check current AusPayNet BECS Procedures.

Engineering Notes

// Conceptual: calculating net position per bank pair
Map<String, BigDecimal> netPositions = payments.stream()
    .collect(Collectors.groupingBy(
        p -> p.getSenderBic() + "_" + p.getReceiverBic(),
        Collectors.reducing(BigDecimal.ZERO, Payment::getAmount, BigDecimal::add)
    ));

// Net: A→B $1M, B→A $600K → one net settlement of A paying B $400K

Store clearing obligations in an immutable ledger — never modify posted obligations
Track clearing cycle state machine: SUBMITTED → NETTED → SETTLED
Implement idempotent settlement status updates (network retries)
Publish clearing position events for real-time monitoring

Interview Questions

Q: What is the main systemic risk of DNS and how is it mitigated?

If a participant fails before settlement, all obligations of that participant must be unwound, potentially cascading to other participants. Mitigated via: loss-sharing agreements, default funds, collateral requirements, position limits, and central bank liquidity backstops.

Q: Why don't all payments use RTGS if it has lower settlement risk?

RTGS requires full liquidity for every payment immediately, which is expensive. DNS is far more liquidity-efficient (only net positions need funding). Most retail-volume, lower-value payments use DNS because the systemic risk is managed through scheme rules rather than eliminated through immediate settlement.

Key Insight

NPP is unique in being both a real-time customer experience (instant credit) AND RTGS settlement (via RBA FSS). Most other real-time payment systems globally use DNS with deferred settlement — NPP's architecture eliminates the gap.