What an IBOR actually is (and why ABOR is not the same book)
An IBOR gives portfolio managers an intraday, position-level view built for decisions; an ABOR gives accounting an end-of-day, valuation-grade view built for NAV. Firms that run one book for both jobs end up reconciling forever.
Two books, two jobs
Ask five people in a fund shop what the "book of records" is and you get five answers. That is not sloppiness — it is because two different books genuinely exist.
IBOR — investment book of records. Built for the desk. Intraday, includes pending and expected activity, reflects the manager's economic view of positions right now. It answers: what can I trade?
ABOR — accounting book of records. Built for fund accounting. Struck end-of-day on settled activity with validated prices. It answers: what is the fund worth, defensibly?
Where it breaks
- Corporate actions land in one book before the other.
- Cash forecasting differs: the desk wants expected cash, accounting wants settled cash.
- Multiple custodians deliver positions on different cut-offs.
What a consultant does here
Map the golden source per data object, not per system. Then decide which breaks are worth automating and which are simply timing differences to be explained.