E-04 — Holding / Position

What the investor owns: a position in an instrument or asset (E-02), within a portfolio (E-03), at a point in time. The entity every exposure, risk and performance calculation ultimately reads from. Held at two grains — the real-time IBOR view and the official accounting-basis ABOR view.

Purpose

A holding is the answer to “what do we own, how much, in which portfolio, as of when.” It is the spine of the operating model: every number about the investor’s investments — exposure, concentration, performance, NAV — is computed from holdings. It is genuinely universal: a position in a listed equity, a government bond, a listed future, an OTC swap, an LP interest in a private fund, or a directly-held building is, in each case, a Holding / Position. What differs is the instrument it points to and how that instrument is valued — not the holding entity itself.

OpenIM models the holding at two books of record, because the buy-side keeps two and they are not the same number on the same day:

• IBOR — the real-time, intraday view the front office trades and manages against.
• ABOR — the official, accounting-basis view used for NAV, financial reporting and audit.

The two are reconciled (SD-12.10); the model keeps them distinct rather than asserting a single position.

Attribute schema

Notes

• The primary key is the composite (position_id, book) — book is in the identity, not merely an attribute. A logical holding keeps one position_id across both books; the book value distinguishes its IBOR record from its ABOR record, which are reconciled against each other (SD-12.10) precisely because they are two records of the same thing that may not agree on a given day. position_id alone is not unique across the two books.
• position_id is the logical-holding identity, shared across both book-rows — and that is the grain other entities reference E-04 at when the fact they record is book-agnostic. A row of E-04 is identified by the composite (position_id, book), but position_id on its own names the logical holding across both books. An entity whose fact attaches to the logical holding regardless of book references E-04 by position_id alone: a Valuation (E-07) — a mark applies to both the IBOR and ABOR view, and feeds the market_value_usd of both rows — and a Securities Loan (PB-10) — one lent-security relationship, not a per-book record. An entity whose fact is genuinely book-specific would carry the composite (position_id, book) instead; none does today. So position_id serves two roles: part of the composite row-identity, and the book-agnostic logical-holding handle that book-agnostic referencers use.
• A position references the universal Instrument / Asset (E-02). A position in a fund interest carries a commitment_usd and an undrawn portion; a position in a listed instrument carries a quantity; a position in a directly-held real asset carries neither in the same sense. The holding entity is the same; the instrument it points to differs.
• The position’s value comes from E-07 Valuation — an observable price for a liquid instrument, a mark-to-model or manager NAV for an illiquid one. The holding records the value; the valuation entity records how it was arrived at.
• Look-through: a position in a fund interest is the LP’s holding; the fund’s own holdings in portfolio companies are modelled in the private-markets pack (PM-09 Fund Investment), and SD-07.5 Look-Through Exposure Analysis decomposes the one into the other.

Out of scope

• The event that moved a holding to its current state — that is E-05 Transaction; E-04 is the state a transaction leaves behind, not the event.
• How a holding’s value was arrived at — that is E-07 Valuation; E-04 records the resulting market_value_usd but not the method, source or confidence behind it.
• A fund’s own holdings in portfolio companies — the investor’s holding is a position in a fund interest; the fund’s underlying holdings are PM-09 Fund Investment, reached by look-through.
• The instrument or asset a position is in — that is E-02 Instrument / Asset, which E-04 references through instrument_id.

Owned and consumed by

• Owned by: key-partitioned by the book attribute, which is part of E-04’s identity — every instance is a position in a named book. SD-12.1 Investment Book of Record (IBOR) is the sole authoritative source for instances where book = ibor; SD-12.2 Accounting Book of Record (ABOR) is the sole authoritative source for instances where book = abor. The two Service Domains are co-equal owners of their partitions — neither holds schema authority over the other; the schema is the model’s, defined once for E-04. The two books diverge intraday and are reconciled by SD-12.10. Consumers must declare which book they consume — the front office reads book = ibor; SD-12.9 Fund Accounting & NAV, SD-09 Performance & Analytics, the BD-16 reporting capabilities (SD-16.2 / SD-16.3 / SD-16.4) and BD-14’s internal-control attestation (SD-14.7) read book = abor; BD-07 Investment Risk reads ibor for intraday measures and abor for period-end. The full pattern is documented in ownership-map.md.
• Consumed by: SD-07 Investment Risk (all domains), SD-09 Performance & Analytics, SD-05.2 Portfolio Management & Monitoring, SD-12.10 Reconciliation, SD-13.10 Investment Reporting & Dashboards — effectively every domain that reasons about what the investor owns.

Open extensions

• Lot-level detail for tax-lot accounting.
• The IBOR / ABOR reconciliation model — how the two books differ and how breaks between them are tracked.
• The corporate-action adjustments that change a position between valuation dates (public-markets pack).