Fusion's multi-ledger architecture mapped to D365 ledgers, posting layers and consolidation

What a Fusion Secondary Ledger and Reporting Currency actually did, what D365's flatter one-ledger-per-legal-entity model replaces them with, why Subledger Accounting made multi-GAAP parallel accounting tractable and what takes its place, and how to choose between a posting layer, a reporting currency, a new legal entity, an extra dimension or a consolidation company for a new accounting requirement.

What you will be able to do

Introduction

Every other unit in this course can be read, broadly, as "here is where D365 is different, and here is how to get the same outcome." This one cannot be read that way entirely honestly.

The D365 ledger object, and what becomes immutable after posting

A D365 legal entity has exactly one Ledger. The Ledger record itself bundles a chart of accounts (plus its account structures), a fiscal calendar (a legal-entity-specific copy of a shared calendar definition), an accounting currency, an optional reporting currency, and the exchange rate types used to convert between them.

Fusion's Primary/Secondary/Reporting-Currency architecture and the four Cs

Setting up Fusion's Accounting Configuration means choosing four things for every ledger, often shorthanded as the four Cs: Chart of Accounts, Calendar, Currency, and (Subledger) Accounting Method.

What a Secondary Ledger actually did — and what replaces it in D365

The reason a Secondary Ledger's independent rule stack matters so much is worth stating precisely: because Subledger Accounting Method is bound one-to-one to a Ledger, and every Application Accounting Definition, Journal Line Rule and Account Rule sits beneath that binding, one operational event could be accounted for correctly under…

Currency: accounting, reporting, transaction and revaluation

The structural point worth dwelling on is that Fusion's Reporting Currency is its own ledger-type object, while D365's reporting currency is only a field on the single Ledger record — it cannot be closed independently, has no separate period status, and is not a distinct configuration surface. That has a sharp practical consequence.

Fiscal calendars, period status and year-end close

Fusion's period status is tracked per Ledger per period — Open, Closed, or Permanently Closed — and its GL close sequence runs in order: complete Subledger Accounting event processing across all modules, run the GL Transfer, reconcile subledger balances to GL control accounts, post foreign-currency revaluation, run intercompany…

Consolidation and elimination

A Fusion Ledger Set is processing convenience, not consolidation. Actual group reporting in Fusion is either a basic in-application Consolidation Ledger — one accounting/reporting currency pair per run — or, for anything with multiple ownership percentages, multi-level currency roll-ups, or heterogeneous source systems, the fuller Oracle…

Decision tree: choosing the right container for a new accounting requirement

Use this sequence for every new accounting requirement that surfaces during design — a new statutory book, a new jurisdiction, a new analytical cut, or a new group-reporting need.

Worked example: one group, four countries, five requirements

A fictitious Northwind Group is headquartered in the United States on US GAAP, with a wholly owned UK subsidiary, a German subsidiary, and a Mexican subsidiary.

Knowledge check

Summary

D365's ledger model is flatter than Fusion's by design, and for one specific case — a Secondary Ledger with a genuinely independent accounting-treatment rule stack — there is no configuration-only replacement. Everything else has a real, if differently shaped, answer.