Australian Market Architecture · Practitioner Handbook · Regulatory Reference

Australian Cash Equity Market Clearing & Accounting Handbook

A practitioner reference guide for Australian cash-equity market clearing, multi-book ledger accounting, subregister mechanics, and Broker-Day settlement obligations under ASX and ASIC regulatory frameworks.

How to Use This Handbook#

1. Read as a Technical Reference: Review sequential chapters for market structure, subregister conversions, double-entry ledger rules, and Broker-Day obligations.
2. Interactive Validation: Launch the live clearing sandbox at simulators.aegissytems.com to simulate bilateral DvP matching, batch netting, and Section 981B trust rebalances.
3. Download / Print: Click Print / Save A4 PDF in the sidebar or press Cmd+P / Ctrl+P to generate an A4 printable manual.

Reading order

1. The market is not one computer#

Australia’s listed cash-equity market is several legal books next to each other. Aegis implements your books and ISO to CHESS.

Under CHESS Replacement, Release 1 covers AMO FIX Trade Capture, while participant post-trade clearing operates under Release 2 ISO 20022 messaging standards.

2. Who talks to whom#

Client  ←—— orders, money, CN, statements ——→  Broker (Aegis)
                                                     │  ISO / SI / holders
                                                     ▼
                                              CHESS (CSD)

Client  ——— issuer-sponsored only ———→  Share registry (SRN)

If someone says “the client sent a message to CHESS”, they mean you sent it.

3. How a share moves#

1. Confirm HIN (APG 7.1) or SRN if still issuer-sponsored.
2. Exchange prints a trade upon execution.
3. ASX Clear novates — market obligation is vs the CCP.
4. Participant house DvP on fill (TRADE_DVP or INSUFFICIENT on the contract). Participant accounting record, not legal title.
5. Contract is the settlement gate (contract). Match path requires a note; direct (insto) may omit.
6. SI (sett_105) tells CHESS deliver/receive. Title has not moved.
7. Batch (live T+2): CHESS moves stock; PayFac moves participant net cash. Ack must not post house again.
8. 6.3B: sell client → Accumulation → Settlement (or straight to Settlement). Buy: Settlement → client HIN (not via Accumulation) + 4.23 / 4.24 / GN 12.
9. Trust: buy money in trust before/with delivery into the client name. Sell receivable into trust, then payout. Principal/firm excluded (6.3B.8).

sett_119 is a settlement acknowledgement, not an internal Rule 6.3B movement.

4. Names and four books#

Do not conflate these identifiers. Institutional clearing architecture strictly separates legal party identifiers, holding subregisters, and general ledger chart rows. Client accounts are settlement HINs, not chart rows.

1. HIN equity tape     /ledger /journal          OR 6.3 HIN
2. Client trust cash   /entrepots/trust          Clear 4.23 (not a HIN type)
3. Control GL          /control-accounts         TRUST_BANK PAYFAC wash
4. House chart         /ledger-accounts          P&L / banks / SUSPENSE
   (+ posting-maps)                              resolve(mapKind) → chart

Derivatives are a fifth tape (AccID). Do not merge.

Cash trap: journal DEBIT cash increases; CREDIT cash decreases. Stock is LONG/SHORT only. TRUST on a HIN leg is a memo — trust cash is GET /entrepots/trust.

5. When postings fire, what you can configure#

Hot path = fill only. Everything else is warm. Catalog: GET /house-postings/catalog.

Configurable General Ledger Setup

1. POST /ledger-accounts — open a row (INCOME / EXPENSE / BANK / ASSET / LIABILITY / SUSPENSE).
2. POST /posting-maps — point a named mapKind at it. Kinds: FEE GST STAMP COMMISSION FAIL_LEVY WRITE_OFF WITHHOLDING BANK_RECEIPT BANK_PAYMENT PAYFAC MARKET_NET SUSPENSE. Longest match. Miss → SUSPENSE or 400.
3. POST /posting-maps/resolve then desk-post {mapKind, amount}.

curl -s -X POST https://simulators.aegissytems.com/api/matching/ledger-accounts \
  -H 'Content-Type: application/json' \
  -d '{"ledgerAccountId":"MY_FEE_INCOME","name":"My fee","kind":"INCOME"}'

curl -s -X POST https://simulators.aegissytems.com/api/matching/posting-maps \
  -H 'Content-Type: application/json' \
  -d '{"mapKind":"FEE","ledgerAccountId":"MY_FEE_INCOME"}'

Not configurable (by design)

6. Account types → which book#

Three axes. Do not invent retail / nominee / institutional as CHESS enums.

OR 6.3 on the HIN

equity account kind — does this book have a HIN?

SUSPENSE is a chart control account. Control CLIENT_MONEY is keyed HIN:{clientHin}, not accountId.

7. Retail broker#

CHESS classification: Participant Sponsored HIN. Controlling participant holds general settlement admission with full bilateral and batch settlement capability.

1. Client Static Record: Create party identity record with KYC/AML verification flags.
2. Sponsored HIN Allocation: Open Sponsored HIN equity account (cash settlement method HOLD or DVP; contract note delivery EMAIL). Queue acmt.001 to CHESS to allocate registration.
3. Tax & Bank Lodgement: Lodge holder TFN/ABN and authorized bank account details.
4. Section 981B Trust Deposit: Verify client money receipt into trust before executing Rule 6.3B buy settlement.
5. Trade Execution & Confirmation: Match order, record house DvP, and issue ASIC MIR 3.4.1 compliant contract note.

8. Institutional broker#

Settlement OR does not define a parent HIN that owns children. Block fills book on a desk id; title lands on each child’s own HIN (or a custodian HIN at another PID) via 6.3B. chessParentHin=false.

1. Block fills on a parent booking (no parent HIN).
2. POST /allocations — qty to child HINs.
3. Each child → Contract → SI (or BS/BD). Or skip the CLOB: contract with an external trade ref.
4. Principal-with-client crossing: MIR 3.2.4 (mir324BrokerageZero).

Standard workflow for institutional block agency executions, custodian allocations, and crossing desks.

9. Issuer-sponsored SRN#

Two subregisters. Aegis is not a share registry. SRN never keys the house tape. Kind ISSUER_SRN does not flip to SPONSORED_HIN on convert — land on an existing HIN (lab 1002) or open sponsored + requestHin first.

Conversion (ISS↔CHESS conversion) = Same legal owner; units move between Issuer-Sponsored SRN and Participant-Sponsored HIN. Not a market sale.
Transfer (ISS↔CHESS transfer) = Ownership changes off-market; registry transfers units between SRN holdings.
Shunt (Foreign Register Shunt) = Cross-border register movement between Australian subregister and foreign exchange depository.

Upon submission, an ISS→CHESS conversion moves to PENDING status. The share registry authenticates the SRN holding and returns AUTHORISED (hold_205 / sese.024), crediting units onto the participant's controlled HIN.

# Standing SRN, then convert onto HIN 1002
curl -s -X POST https://simulators.aegissytems.com/api/matching/client-accounts/CA-SRN-DEMO/srns \
  -H 'Content-Type: application/json' \
  -d '{"securityCode":"BHP","srn":"I0000123456"}'

curl -s https://simulators.aegissytems.com/api/chess/conversions
curl -s -X POST https://simulators.aegissytems.com/api/chess/conversions/inbound \
  -H 'Content-Type: application/json' \
  -d '{"conversionId":"CNV-1"}'
# AUTHORISED → HIN 1002 BHP +10. srn absent on /ledger

10. Corporate actions on HIN vs children#

seev.* is the event store — it does not post. After record, apply the HIN so chess-recon matches. Fixture ticker CAX. SRN → 400.

nominee entitlement split (same apply call): ratio = child projector qty ÷ parent HIN holding. Residual rounding follows participant allocation rules. Dust stays on the parent HIN. Legs: SHORT/CREDIT parent HIN, LONG/DEBIT child accountId. CHESS still one holding. Recon stays HIN-keyed. Event CorporateActionDistributedEvent.

curl -s -X POST https://simulators.aegissytems.com/api/chess/diary/apply \
  -H 'Content-Type: application/json' \
  -d '{"hin":1002,"eventId":"EVT-BHP-DIVIDEND"}'

Corporate action events are recorded in event subregisters prior to application. Takeover reserves isolate participating units. Claims outside CHESS are tracked without duplicating house postings.

11. Principal, house contracts, crossings, brokerage#

Settlement OR does not set brokerage. Three questions: capacity on the trade (MIR), client money on 6.3B (6.3B.8), and whether you may charge the client when you are Principal with them (MIR 3.2.4).

# Principal CN — brokerage/gst/fee wiped; stamp 8 kept
curl -s -X POST https://simulators.aegissytems.com/api/matching/contracts \
  -H 'Content-Type: application/json' \
  -d '{"tradeId":2,"hin":1002,"securityCode":"BHP","quantity":10,"price":4500,"capacity":"PRINCIPAL","brokerage":50,"gst":5,"stampDuty":8}'

Client confirmation contract notes must explicitly state principal capacity in compliance with ASIC Market Integrity Rule 3.2.3 and 3.4.1. Under MIR 3.2.4, brokers executing trades as principal against client orders are prohibited from charging brokerage fees unless an approved exemption applies.

12. Interactive Scenarios & Simulator Workflows#

Market clearing workflows involve interacting systems across matching venues, CSD settlement engines, subregisters, and double-entry general ledgers. You can step through and execute these live scenarios directly inside the Aegis Simulator Cockpit.

Each scenario updates the CHESS ISO 20022 message log, participant holding balances, and double-entry ledger batches in real time.

13. Broker-Day obligations — what you see, what you do#

Fulfilling the market is two layers. A local CLOB fill is houseInternal — it is not the CHESS net. A fill can succeed while the blotter still says source: NONE.

CHESS  ←—— batch DvP ——→  Settlement Entrepot (HIN 1004)
                                 │  6.3B (you)
                                 ▼
                          Client HIN / trust

Hub widgets

Blotter rows → action

DIRECT / PRINCIPAL: no client trust amount on HIN 1001 (6.3B.8). 6.3B.4 to DIRECT with trust → 400.

curl -s -X POST https://simulators.aegissytems.com/api/matching/entrepots/transfers \
  -H 'Content-Type: application/json' \
  -d '{"rule":"6.3B.1","fromHin":1002,"toHin":1003,"quantity":60,"ownerHin":1002,"securityCode":"BHP"}'
curl -s -X POST https://simulators.aegissytems.com/api/matching/entrepots/transfers \
  -H 'Content-Type: application/json' \
  -d '{"rule":"6.3B.2","fromHin":1003,"toHin":1004,"quantity":60,"trustAmount":22500,"ownerHin":1002,"securityCode":"BHP"}'

Prime the exact net delivery gap (100 sell units minus 40 buy units = 60 net units).

14. If a break is observed#

A break is a mismatch between two books, not a crash. Classify first. Do not post house on a CHESS ack to “fix” it. Start Operations Desk, then the book that should have moved.

15. Historical incidents — what Aegis can mitigate#

Aegis cannot keep CHESS or ASX Trade up. It can keep your books honest. Never mitigate here: venue down, RITS down, CCP default waterfall.

16. Reference Market Cast & Regulatory Standards#

Standard reference identifiers used across market clearing simulations and participant books:

Authoritative Regulatory Specifications

This handbook is maintained as an independent practitioner technical reference for Australian financial market infrastructure.