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IAS 36 Impairment of Assets: Complete Guide with Goodwill, CGU & Valuation

By Usman Qureshi (ACCA, ACA) · Published July 2026 · Last reviewed July 2026 · 16 min read

IAS 36 (Impairment of Assets) is where auditors spend serious time. Goodwill impairment, Cash-Generating Unit (CGU) identification, fair value measurement, value-in-use calculations with WACC— all carry significant judgment and all are audit hot spots. This guide covers the full impairment testing model with worked examples, real company case studies, and the red flags auditors hunt for.

In this guide

IAS 36 Scope and Framework

IAS 36 applies to all assets except:

The core principle: an asset is impaired if its carrying amount exceeds its recoverable amount (the higher of fair value less costs and value-in-use).

Impairment Indicators: When to Test

You must test for impairment if there are external or internal indicators that an asset may be impaired:

External Indicators

Internal Indicators

Audit focus: Did management identify indicators during the year? Many companies miss them. Auditors will specifically look for external/internal events and challenge if impairment wasn't tested.

Cash-Generating Units: Identification & Allocation

A CGU is the smallest identifiable group of assets that generates independent cash flows.

Examples of CGU Identification

Entity Type CGU Definition Why
Retail chain Individual store or store cluster Each store generates separate cash flows; can be tested/sold independently
Manufacturing (multi-product) Production line or division Each line has distinct cash flows and customer base
Software company Each product (SaaS subscription, license) Different revenue streams, customer bases, margins
Bank (multi-business) Retail banking, investment banking, trading Distinct cash flows and risk profiles

Recoverable Amount: Fair Value vs Value-in-Use

Recoverable Amount = Higher of:
1. Fair Value Less Costs of Disposal (FVLCD)
2. Value-in-Use (VIU)

Fair Value Measurement

FVLCD is what you'd get if you sold the asset today in an orderly transaction.

Valuation Approach: Three Methods

Value-in-Use: Discount Rate (WACC) & Cash Flows

VIU = PV of future cash flows the asset is expected to generate over its life.

Three Components

WACC Formula

WACC = (E/V × Cost of Equity) + (D/V × Cost of Debt × (1 −’ Tax Rate))

Where:

WACC Example
Company's capital structure: 60% equity, 40% debt
— Cost of equity: 10% (risk-free rate 3% + Beta 1.4 × 5% equity risk premium)
— Cost of debt: 5%
— Tax rate: 20%

WACC = (60% × 10%) + (40% × 5% × (1 −’ 20%))
= 6% + (2% × 0.8)
= 6% + 1.6% = 7.6%

Goodwill Impairment Testing

Goodwill must be tested annually (or whenever indicators arise). No exceptions.

Allocation Process

  1. Identify the CGU(s) that benefited from the goodwill acquisition
  2. Allocate goodwill to each CGU
  3. Test the CGU (including allocated goodwill) for impairment
  4. If CGU's recoverable amount < carrying amount, impair goodwill first

Worked Example: Goodwill Impairment

Scenario: Acquisition of Tech Startup

Impairment Test (31 Dec 2025): Revenue Down 30%

Journal Entry

Dr Impairment Loss (P&L) £5,000,000
    Cr Goodwill £5,000,000

Goodwill reduced from £15m to £10m. Future periods: goodwill is retested; additional impairments likely if Tech Startup remains underperforming.

Real Company Example: Unilever's Acquisition Writeoff (2017)

Unilever acquired Tresemmé/Sun Silk hair brands for ~£850m in 2014. In 2017, facing sluggish sales and market consolidation, Unilever wrote down ~£650m of the goodwill. The impairment test showed that value-in-use (based on updated cash flows) fell significantly below the acquisition price due to:

Audit Red Flags in IAS 36

Red Flag 1: No Impairment Test Despite Indicators

Finding: Company's revenue dropped 25%, but management didn't test goodwill for impairment.

Auditor action: Perform impairment test yourself; likely find significant impairment required.

Red Flag 2: Overstated Terminal Value Growth

Finding: VIU assumes 4% perpetual growth, but long-term GDP growth is 2% and the company faces headwinds.

Auditor action: Reduce terminal growth to GDP proxy; increases discount rate; reduces recoverable amount →’ impairment.

Red Flag 3: Underestimated Discount Rate (WACC)

Finding: WACC is 5%, but company's debt is speculative-grade; cost of debt should be 8%+.

Auditor action: Recalculate WACC with risk-adjusted rates; typically increases WACC by 1— 2%, reducing VIU significantly.

Red Flag 4: No Sensitivity Analysis

Finding: Impairment model shows no sensitivity to changes in key assumptions (WACC, growth rate).

Auditor action: Require sensitivity analysis; if impairment is near the threshold, small assumption changes flip the outcome.

IAS 36 vs ASC 350/360 (US GAAP)

Key difference: Two-step goodwill test (ASC 360). Step 1 tests if impairment is likely (qualitative); Step 2 measures it (quantitative). IFRS uses simpler single-step (direct VIU/FV comparison). But both eventually reach the same conclusion.

Real-Life Case Study: Impairment After a Lost Contract

Scenario. A company's cash-generating unit (a factory) loses its largest customer, a clear impairment indicator. The CGU's carrying amount is £8m.

Test. Recoverable amount is the higher of fair value less costs of disposal (£5.5m, from a broker estimate) and value in use (£6.2m, from discounted cash flows). Recoverable amount = £6.2m, so an impairment loss of £1.8m is recognised, first against any goodwill, then pro-rata across the CGU's other assets.

Takeaway. You only need one of the two measures to exceed carrying amount to avoid impairment, so preparers often start with whichever is easier to support. Once impaired, non-goodwill assets can be reversed later if conditions improve, goodwill impairment never reverses.

Illustrative composite scenario for educational purposes. Figures are indicative and do not represent any specific company.

Related Articles in This Cluster

• IAS 36 CGU Identification: Allocation & Testing

• IAS 36 Value-in-Use: Calculating WACC, Terminal Value & Discount Rate

Disclaimer: This is educational content. IAS 36 impairment testing involves complex valuations and professional judgment heavily scrutinized by auditors. Consult a qualified accountant or valuation specialist for your specific circumstances. WACC calculations, terminal growth assumptions, and CGU definitions are common areas of audit challenge and adjustment.