CGU vs Business Segment Impairment
CGU vs business segment impairment — what each unit is, why it matters for goodwill impairment under IAS 36 and IFRS 8, and how CFOs reconcile the two.
Introduction
Two unit-of-measurement concepts sit at the heart of intangible-asset impairment testing and segment disclosure: the cash-generating unit (CGU) under IAS 36, and the operating segment or business segment under IFRS 8 (UK and global IFRS) and ASC 280 (US GAAP). They are related but distinct, and they answer different questions.
The CGU is the smallest identifiable group of assets that generates largely independent cash inflows from continuing use. Goodwill is allocated to one or more CGUs and tested for impairment at that level. The operating segment is the unit at which the chief operating decision maker (CODM) makes decisions about resource allocation and performance assessment. Disclosure under IFRS 8 / ASC 280 is at the operating-segment level.
CGUs and operating segments are often related but not identical. A single operating segment may contain multiple CGUs. The boundary choice has real consequences: goodwill impairment is tested at the CGU level, but the test cannot exceed the operating segment that contains the CGU (IAS 36 paragraph 80). Where the CGU boundary is drawn affects both the headroom calculation and the disclosure narrative.
TL;DR: A CGU is the smallest group of assets generating largely independent cash inflows; it is the unit of measurement for impairment testing under IAS 36. A business segment (operating segment under IFRS 8 / ASC 280) is the unit at which the CODM allocates resources and assesses performance; it is the unit of measurement for segment disclosure. CGUs and operating segments can coincide, but the CGU is typically smaller. Goodwill impairment is tested at the CGU level, capped at the operating segment containing it.
Cash-Generating Unit (CGU)
A CGU is the smallest identifiable group of assets that generates cash inflows that are largely independent of the cash inflows from other assets or groups of assets. Defined in IAS 36 paragraph 6, the CGU is the unit of measurement for impairment testing.
CGUs exist because most assets do not generate cash flows on their own — they generate value as part of a wider operational unit (a factory, a brand, a regional business, a product line). The CGU is the smallest level at which independent cash flows can be identified.
How CGUs are identified
- Start at the asset level — can the individual asset generate cash flows independently of other assets?
- If not, expand the boundary to include other assets that together generate independent cash flows
- The test of "largely independent" is binary — minor inter-dependencies (shared overheads, occasional cross-CGU customer overlap) are acceptable
- The CGU boundary should be consistent year-on-year unless the underlying operations have genuinely changed
- Goodwill is allocated to one or more CGUs or groups of CGUs that benefit from the synergies of the acquisition
Where CGU boundaries typically sit
- Single-site businesses: one CGU (the whole business)
- Multi-site retail: typically each store is a CGU; the network may be a CGU group
- Manufacturing: typically each factory or each product line
- Service businesses: typically each major service line or geographic region
- SaaS: typically each platform or major product line; some integrated platforms are a single CGU
What goes into the CGU carrying amount
- All directly attributable identifiable assets and liabilities of the CGU
- Allocated goodwill (where the CGU is the level of goodwill allocation)
- Allocated corporate assets (where they relate to the CGU)
- Working capital directly attributable to the CGU
A UK retail group operates 38 stores across three regional clusters. The impairment policy allocates goodwill to the three regional CGUs, with each store treated as a CGU for impairment-indicator purposes and the cluster as the CGU group for goodwill allocation. The choice reflects the operational reality: each store generates largely independent cash flows, but goodwill from the 2022 acquisition was paid for regional market position, not individual stores. The impairment test is performed at the cluster level (where the goodwill sits) and at the individual-store level where indicators arise.
Operating Segment / Business Segment
An operating segment is a component of an entity that engages in business activities, whose results are regularly reviewed by the CODM (chief operating decision maker) to allocate resources and assess performance, and for which discrete financial information is available. Defined in IFRS 8 paragraph 5 (UK and global IFRS) and ASC 280-10-50-1 (US GAAP), the operating segment is the unit of measurement for segment disclosure.
The CODM is typically the CEO or the executive committee — the highest-level function reviewing segment performance for resource-allocation purposes. Operating segments mirror the entity's internal management structure rather than its legal or geographic structure.
How operating segments are identified
- Identify the CODM and the segments at which the CODM reviews performance
- Apply the quantitative thresholds in IFRS 8 paragraphs 13-15 (10% of revenue, 10% of profit/loss, 10% of assets) to identify reportable segments
- Aggregate operating segments where the aggregation criteria are met (similar economic characteristics, products, customers, production processes, regulatory environment)
- Disclose each reportable segment separately under IFRS 8 paragraphs 22-23
Typical operating segments
The IFRS 8 / ASC 280 framework is principles-based and reflects each entity's management structure. Typical patterns:
- Multi-product business: segments by product line
- Multi-geography business: segments by region or country
- Multi-business-line group: segments by business line
- Integrated business: a single reportable segment
What disclosure is required for each operating segment
- Revenue (external and intersegment)
- Profit or loss measure used by the CODM
- Assets (where presented to the CODM)
- Liabilities (where presented to the CODM)
- Key reconciling items between segment totals and entity totals
- Information about major customers, geographic information, and product/service revenue
A UK manufacturing group reports three operating segments to its board (the CODM equivalent): Consumer Products, Industrial Components, and Services. The segments meet the IFRS 8 quantitative thresholds and are not aggregated. Within Consumer Products, the impairment team identifies three CGUs (each a product family); within Industrial Components, two CGUs (each a manufacturing site); within Services, a single CGU. Six CGUs in total across three operating segments. Goodwill from the 2023 acquisition sits in the Consumer Products operating segment and is allocated to the three CGUs within it.
Side-by-Side Comparison
The table below contrasts the two units of measurement.
| Criterion | CGU | Operating Segment |
|---|---|---|
| Purpose | Unit of measurement for impairment testing | Unit of measurement for segment disclosure |
| Standard reference | IAS 36 paragraphs 6, 68, 80-90 | IFRS 8 (UK and global); ASC 280 (US GAAP) |
| Test | Smallest group of assets generating largely independent cash inflows | Component reviewed by CODM for resource allocation and performance assessment |
| Defining viewpoint | Cash-flow independence (operational) | Management reporting (internal control) |
| Typical scale | Smaller — often a site, product line, or regional cluster | Larger — typically a business line, geographic region, or product category |
| Relationship | One operating segment may contain multiple CGUs | Equal to or larger than the CGUs within it |
| Goodwill allocation | Allocated to CGUs (or CGU groups) that benefit from the acquisition | Goodwill is disclosed at operating-segment level but tested at CGU level |
| Frequency of review | At least annually for goodwill and indefinite-life intangibles | At each reporting period |
| Quantitative thresholds | No formal threshold — judgement-based | 10% revenue / 10% profit-or-loss / 10% assets |
| Aggregation rules | Not aggregated — each CGU tested separately | Permitted under IFRS 8 paragraph 12 / ASC 280 where economic characteristics are similar |
| Disclosure requirement | IAS 36 paragraph 134 — CGU-level impairment disclosure | IFRS 8 / ASC 280 segment disclosure |
| Audit focus | Boundary consistency, independence of cash flows, allocation rationale | CODM identification, threshold application, aggregation justification |
| Year-on-year stability | Should be stable unless operations have genuinely changed | Should be stable unless reporting structure has genuinely changed |
| Upper boundary | Cannot exceed the operating segment that contains it (IAS 36 paragraph 80) | Bounded by the entity itself |
| Common error | Drawing CGU boundaries too wide to maximise headroom | Aggregating segments without meeting the aggregation criteria |
How CGUs and operating segments interact in practice
The relationship is hierarchical: operating segments contain CGUs. Three patterns are common:
- CGU = operating segment. A simple integrated business with a single product line or service may have one operating segment that is also a single CGU.
- CGU < operating segment. The most common pattern. An operating segment contains 2-5 CGUs reflecting the operational sub-structures (sites, regions, product families) within it.
- CGU group < operating segment. Goodwill allocated to a CGU group within an operating segment — for example, a regional cluster of stores within a Consumer Products segment.
The IAS 36 paragraph 80 cap is important: the unit for goodwill impairment testing cannot be larger than the operating segment determined under IFRS 8. This prevents entities from artificially expanding the CGU boundary to capture headroom from operationally independent businesses.
CGUs and operating segments answer different questions. CGUs are the smallest unit of independent cash flows; operating segments are the largest unit of management reporting that is below entity level. Goodwill impairment is tested at CGU level but capped at operating-segment level. The two units should be considered together — not interchangeably.
Why the Distinction Matters
Three areas drive the practical importance.
Impairment headroom. A wider CGU boundary captures more cash flows and produces more headroom. The temptation to draw CGU boundaries wide is real and routinely audit-challenged. The IAS 36 paragraph 80 cap prevents the CGU from being wider than the operating segment, but within that ceiling there is judgement. CGU boundaries that move year-on-year without operational justification are a red flag.
Disclosure narrative. IFRS 8 / ASC 280 segment disclosure is the public-facing description of how the business is structured. CGU-level impairment disclosures under IAS 36 paragraph 134 sit inside this narrative. Inconsistency between segment reporting and CGU allocation (for example, goodwill allocated to a CGU that does not align with the segment narrative) is the kind of presentation issue that prompts analyst questions.
Aggregation discipline. Under IFRS 8 paragraph 12, operating segments can be aggregated if they share similar economic characteristics. Aggregation is permitted but not automatic — the aggregation criteria must be met and documented. Loose aggregation produces oversimplified segment disclosure that masks underlying performance variation, attracting auditor and analyst challenge.
A UK technology group with two operating segments (SaaS and Services) restructured in 2025, merging the two into a single reportable segment under the aggregation criteria. The auditor challenged the aggregation: the two operating segments had materially different gross margins (SaaS 72%, Services 35%), different customer bases, and different production processes. The aggregation criteria were not met. The 2025 financial statements were prepared with two reportable segments, and the impairment test for goodwill (which had been allocated to a single combined CGU under the restructured view) was re-performed at the segment-aligned CGU level. The conclusion was unchanged but the disclosure was strengthened.
FAQ
What is the difference between a CGU and a business segment?
A CGU is the smallest identifiable group of assets that generates largely independent cash inflows under IAS 36 paragraph 6 — used for impairment testing. A business segment (operating segment) is the unit at which the CODM reviews performance for resource allocation under IFRS 8 / ASC 280 — used for segment disclosure. The two answer different questions; the CGU is typically smaller than the operating segment.
Can a CGU be larger than an operating segment?
No — IAS 36 paragraph 80 caps the unit for goodwill impairment testing at the operating-segment level determined under IFRS 8. Within that ceiling, the entity selects the smallest unit that benefits from the synergies of the acquisition.
Why are CGUs not the same as legal entities?
CGUs are operational, not legal. A single legal entity may operate multiple CGUs (a multi-product subsidiary), and a single CGU may span multiple legal entities (an integrated product line spread across two subsidiaries). The CGU follows the cash-flow independence test, not the legal structure.
How often should CGU boundaries change?
Rarely — only when the underlying operations have genuinely changed. Restructuring, disposals, new product lines, and changes in management responsibility may justify a CGU boundary change. Re-drawing CGUs to manage impairment headroom is a presentation issue auditors challenge directly.
Who is the CODM?
The chief operating decision maker — the function (not necessarily an individual) that allocates resources to operating segments and assesses their performance. Typically the CEO, the executive committee, or the board for smaller entities. IFRS 8 paragraph 7 emphasises function over title.
Can an entity have a single operating segment?
Yes — many entities report a single operating segment under IFRS 8 / ASC 280, particularly entities with a single product line, single geography, or where the CODM does not differentiate performance below the entity level. Single-segment reporting is common in early-stage businesses and pure-play integrated platforms.
What is the relationship between CGU and reporting unit under US GAAP?
The US-GAAP "reporting unit" under ASC 350 is broadly similar to the CGU under IAS 36, but the two are not identical. Reporting unit is one level below operating segment (ASC 350-20-35-33-36). Both are the unit for goodwill impairment testing in their respective frameworks. UK groups consolidating both IFRS and US GAAP entities may need to maintain both CGU and reporting-unit views.
How are corporate assets treated?
Corporate assets (head-office buildings, central IT, group functions) cannot generate independent cash flows on their own, so they are allocated to CGUs that benefit from them on a reasonable and consistent basis. IAS 36 paragraphs 100-103 provide the allocation framework. Where corporate assets cannot be reasonably allocated, the impairment test is performed at the smallest group of CGUs that includes them.
When to Seek Expert Support
The CGU boundary decision is one of the higher-judgement areas in impairment testing. Edge cases — newly acquired businesses with goodwill to allocate, restructuring or disposal events mid-year, integrated platforms where cash-flow independence is borderline, and multi-jurisdictional groups with both CGUs and US-GAAP reporting units — typically warrant specialist input.
Opagio's Asset Valuator module (within Opagio Intangibles) supports impairment work by separating asset-level valuation from CGU-level aggregation. Each identifiable intangible asset is valued at its individual fair value; the model then maps assets to CGUs (and CGU groups) per the entity's allocation policy. The output reconciles the asset-level values to the CGU-level carrying amount and recoverable amount, with the disclosures structured for both IAS 36 paragraph 134 and IFRS 8 segment-level narrative.
For groups with both IFRS and US GAAP entities, the model can map the same intangibles to both the IAS 36 CGU view and the ASC 350 reporting-unit view, so the CFO can see both frameworks' outputs in parallel rather than running two separate processes.
Book a demo: See how Asset Valuator structures impairment work by CGU and CGU group, with goodwill allocation traceable to the operating-segment narrative. Book a demo or speak to our team.
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