OpenIM The Open Investment Model

SD-12.2 — Accounting Book of Record (ABOR)

Business Domain: BD-12 Investment Operations & Servicing (Back office) · Applies: BOTH

Purpose

Maintains the official, accounting-basis book of holdings and balances — the authoritative ledger from which net asset value, financial reporting and audit are produced. Where the IBOR (SD-12.1) is the real-time view the front office trades against, the ABOR is the official record: positions and balances kept on accounting rules, posted to a general ledger, and struck at a periodic book close. It exists because the firm’s official numbers must rest on a controlled, accounting-disciplined book — not the intraday trading view, which is correct for trading but not struck for reporting. It is not the IBOR, and it is not fund-level NAV striking — that is SD-12.9, which maintains the books of funds the institution operates; SD-12.2 maintains the accounting book of the institution’s own portfolios.

Service Operations

  • Accounting-basis position keeping — maintain holdings and balances on the abor book, recognised and measured on the firm’s accounting policy, distinct from the intraday IBOR position.
  • General-ledger posting — translate each transaction and event into the corresponding accounting entries and post them to the investment general ledger.
  • Income and expense accrual — accrue interest, dividends, fees and expenses into the accounting book between cash dates, so the book reflects earned-but-unreceived and incurred-but-unpaid amounts.
  • Cost-basis and lot accounting — maintain the cost basis of each position and, where required, the tax-lot detail, so realised and unrealised gain is correctly measured.
  • Trade-date / settlement-date accounting — recognise transactions on the basis the accounting policy specifies, and carry the difference between trade-dated and settlement-dated views.
  • Book close — run the periodic (daily, monthly, quarterly) close: cut off activity, complete accruals, validate, and lock the accounting book for the period.
  • Adjusting and correcting entries — post the corrections, reclassifications and restatement entries an accounting book requires, under control and with an audit trail.

Inputs and outputs

  • Inputs: transactions and cash flows from SD-12.1 (E-05, E-06); valuations from SD-08; corporate-action and income outcomes from SD-12.6 and SD-12.7; fee, expense and carry amounts from SD-12.11; reconciliation results from SD-12.10.
  • Outputs: the accounting-basis book of holdings and balances, and the investment general ledger — consumed by SD-12.9 Fund Accounting & NAV, SD-09 Performance & Analytics, SD-16.4 Financial Reporting & Disclosure, SD-17.1 Corporate Accounting & Controllership, SD-17.4 Investment & Portfolio Tax, and SD-14.8 Internal Audit.

Entities

  • Consumes: E-05 Transaction, E-06 Cash Flow Event, E-07 Valuation (any method — ABOR applies the official accounting valuation method per fair-value-governance policy), E-03 Portfolio / Mandate; FO-04 Dealing Order (settled dealing orders — the accounting-basis position and cash effects of settled subscriptions, redemptions and switches are booked to the ABOR at the accounting recognition date); FO-05 Fund Distribution Event (the distribution payment is booked as a cash event in ABOR — the declared distribution per unit and the pay-date cash transfer from the fund to investors generate the accounting entries SD-12.2 posts); FO-10 ETF Creation/Redemption Order (settled ETF primary-market creation/redemption events — the accounting-basis position and cash effects of the in-kind basket exchange are booked to the ABOR at the accounting recognition date); the SD-12.1 transactions and cash flows; the SD-12.10 reconciliation results; the SD-12.11 fee, expense and carry amounts; the SD-12.6 corporate-action and income outcomes; the SD-12.7 corporate-action and income outcomes.
  • Owns: E-04 Holding / Position on the abor book — SD-12.2 is the authoritative source for the accounting-basis position. E-04 carries a book discriminator and an accrued_income_usd attribute specifically for the ABOR book. The general ledger itself is an accounting structure; whether OpenIM models a ledger-account entity is an open question — see below.
  • Open question: whether the investment general ledger warrants its own entity (a chart-of-accounts and posting structure) rather than being treated as downstream of E-04 / E-05. Flagged for the open-extensions pass alongside the IBOR / ABOR reconciliation model.

Standards

  • IFRS / local GAAP — the accounting standards the book is kept to; IFRS 9 governs the classification and measurement of financial instruments, IFRS 13 fair-value measurement.
  • ISO 20022 messaging carries the transaction and event data the ledger is posted from.
  • The IBOR / ABOR distinction is a recognised buy-side operating-model pattern, reflected in the platform vendor stacks; the ABOR is the side those stacks built their fund-accounting modules around.

Open extensions

  • The Service-Operation-level input/output contracts.
  • Whether a general-ledger / chart-of-accounts entity is warranted — the open question above.
  • The trade-date vs settlement-date accounting sub-model, and how the two views reconcile to the IBOR.

Built from open-investment-model v0.3.0 · f7452ad