IFRS 18 Transition Plan: A Phased Practitioner Roadmap for 2026

IFRS 18 is mandatory for annual periods beginning on or after 1 January 2027, and retrospective application is not optional. That means your 2026 financial data must be captured and classified under the new standard from day one of 2026. If you haven't started your IFRS 18 transition plan yet, you're in the majority: a KPMG Q1 2025 webcast survey of over 2,600 respondents found that roughly 80% of IFRS preparers had not yet launched an implementation project. That gap is closing fast.

This guide is for group controllers, CFOs, and external reporting teams who know the standard exists but haven't mobilised. It won't re-explain what IFRS 18 requires at a conceptual level (see our IFRS 18 vs IAS 1 comparison for that). It will tell you what to do, in what order, and by when, including the risks that almost no published guidance addresses: covenant renegotiation, MPM audit exposure, and subsidiary classification divergence.

Key takeaway: For a 31 December year-end, you have roughly 16 months from September 2026 to your first mandatory IFRS 18 filing. The 2026 comparative data capture window is already open. Every week without a project owner is a week of unrecoverable data.

What Does IFRS 18 Actually Require You to Change?

IFRS 18 is a presentation and disclosure standard, not a measurement standard. It doesn't change your profit totals, EPS, or net assets. What it changes is how profit is analysed and presented, and that has cascading operational consequences.

The IASB's April 2024 standard introduces:

• Three mandatory income statement categories: operating, investing, and financing. Operating is the residual, items not classified as investing or financing fall there.
• Two mandatory subtotals on the face of the income statement: operating profit or loss, and profit or loss before financing and income tax. These cannot be omitted.
• A new MPM disclosure note: any subtotal of income and expenses communicated outside the financial statements (earnings releases, investor decks, management commentary) that isn't defined by IFRS must be disclosed in the notes with a reconciliation to the nearest IFRS subtotal, an explanation of why it's useful, and a description of how it's calculated.
• Disaggregation of operating expenses by nature in the notes, regardless of whether the income statement uses a by-nature or by-function presentation. This is entirely new and has no equivalent in IAS 1.

For a deeper look at classifying every P&L line into the three categories, see our IFRS 18 operating, investing and financing categories guide. For the MPM disclosure mechanics, our IFRS 18 management-defined performance measures walkthrough covers the full note construction.

The IFRS 18 Transition Timeline: Phase by Phase

Work backwards from 31 December 2027 (first mandatory filing date for a calendar year-end entity). The table below sets out the four phases and their non-negotiable milestones.

The critical constraint is Phase 3. If your chart-of-accounts changes or subsidiary mapping instructions aren't live by 1 January 2026, you will be reconstructing comparative data from transaction-level records at year-end 2027, under audit pressure, with no margin for error.

Phase 1: Assessment (Q3-Q4 2025)

The assessment phase has four components, and all four must run in parallel:

1. Income statement gap analysis. Map every current P&L line to the three IFRS 18 categories. Flag items where classification is genuinely ambiguous, particularly foreign exchange differences, interest income on working capital balances, and gains/losses on derivatives. EY's IFRS 18 guidance flags the investing category as narrower than most preparers expect: it covers income from assets that generate returns independently of the entity's main business activities, not all investment-related items.

2. MPM inventory. Pull every earnings release, investor presentation, and management commentary from the last 12 months. List every non-IFRS subtotal communicated externally: adjusted EBITDA, underlying EBIT, adjusted operating profit, free cash flow. Each one is a candidate MPM. Decide now which to retain (and therefore disclose in the audited notes) and which to retire. This decision has real consequences, covered below.

3. Systems capability review. Can your ERP and consolidation platform capture income and expenses at the category level at source? Or does it currently aggregate items that will need to be split? The answer determines whether you need a chart-of-accounts redesign, a mapping/overlay layer, or a full ERP configuration change. Each path has a different lead time.

4. Stakeholder identification. IFRS 18 is not a narrow accounting project. KPMG identifies the following functions as requiring early involvement: controllership/external reporting, internal audit, investor relations, IT, HR, treasury, and business operations. Assign a named owner from each function in Phase 1, not Phase 3.

Phase 2: Design and Decisions (Q4 2025 to Q1 2026)

This is the phase where the hard calls get made. Three decisions in particular cannot be deferred.

Decision 1: Chart of accounts vs. mapping overlay. Entities with relatively simple structures can often handle IFRS 18 reclassifications through a mapping layer in their consolidation tool, without touching the underlying chart of accounts. Entities with complex subsidiary structures, or where the disaggregation of operating expenses requires transaction-level data that doesn't currently exist, will need actual chart-of-accounts changes. The latter requires IT project time, testing, and subsidiary rollout, typically 3-6 months minimum. If you're in this camp and haven't started, Q4 2025 is already late.

Decision 2: Covenant and remuneration review. This is the risk almost no published guidance addresses in depth. As KPMG's Ingo Zielhoff and Kayla Molaro note: "Operating profit as defined under IFRS 18 may be different from operating profit as calculated today. This change may affect KPI targets, debt covenants, remuneration agreements and budgeting/performance reporting, if they reference operating profit."

Run the IFRS 18 income statement format against your current debt agreements. If a covenant references "operating profit" or "EBIT" without a precise contractual definition tied to a specific accounting standard, your lenders may interpret the new IFRS 18 subtotal differently from the measure you've been reporting. The same applies to executive bonus schemes that reference operating profit or adjusted EBITDA. Renegotiating these agreements takes time and requires legal involvement. Do it in 2025 or early 2026, not in Q4 2026 when you're also running a parallel close.

Decision 3: MPM list finalisation. Decide which non-GAAP measures survive into the IFRS 18 world. Any measure you retain and communicate externally becomes an MPM, subject to mandatory note disclosure and, critically, audit scrutiny. Grant Thornton's IFRS 18 commentary makes the point that MPMs will, for the first time under IFRS, sit inside the audited financial statements. Companies that have historically used adjusted EBITDA loosely, with inconsistent add-backs or limited documentation, will face auditor challenge on the measure's definition, consistency, and reconciliation. The time to tighten those definitions is now, before the auditors ask.

For a step-by-step guide to building the MPM reconciliation note itself, see our IFRS 18 MPM reconciliation practitioner guide.

Phase 3: Build and Embed (Q1-Q2 2026)

By 1 January 2026, the following must be operational:

• Chart-of-accounts changes or mapping instructions live in all systems
• Subsidiary reporting instructions issued and confirmed
• Training completed for subsidiary finance teams
• Consolidation process updated to handle category-level data

The subsidiary dimension deserves specific attention. KPMG's implementation guidance gives a worked example that illustrates the problem precisely: a subsidiary that earns rental income and classifies it as operating (because rental is its main business activity) may need to have that income reclassified to investing at the group level (because rental is not the group's main business activity). This isn't a top-side journal entry problem. It requires the consolidation process to carry category-level flags through from subsidiary submissions, and it requires subsidiaries to understand why they're being asked to code transactions differently.

As KPMG puts it: "The disaggregation of operating expenses in the notes and proper classification of all items of income and expenses may not be achievable through estimation or top entries. Instead, it may require subsidiaries to follow uniform account mapping and bookkeeping practices."

For groups with 20+ subsidiaries across multiple jurisdictions, this is a programme management challenge, not just an accounting one. Build a subsidiary readiness tracker in Phase 2 and use it actively in Phase 3.

Phase 4: Parallel Run and Lock (Q3-Q4 2026)

The parallel run is non-negotiable. Run your legacy reporting format and your IFRS 18-compliant format simultaneously for at least one full quarter before the year-end close. This gives you time to:

• Identify classification errors before they become comparative restatement problems
• Validate that the two mandatory subtotals (operating profit; profit before financing and income tax) are mathematically consistent across the consolidation
• Test the MPM reconciliation note against actual Q3 numbers
• Give your auditors early sight of the new income statement format and key judgments

The IASB confirmed that IFRS 18 requires full retrospective application under IAS 8. There is a limited relief: entities are not required to disclose the quantitative impact of first-time application if that information is impracticable to obtain. But the restatement of comparative income statement data is not optional. If your 2026 data capture was incomplete, you will be estimating, and auditors will push back.

Who Owns What: A Stakeholder Map

One of the most common failure modes in IFRS 18 projects is the absence of a clear owner. The standard cuts across six functions, and without explicit accountability, each team assumes another is leading.

Appoint a named IFRS 18 project lead from group controllership in Phase 1. That person chairs a cross-functional steering group that meets at least monthly through 2026.

The Investor Communication Risk

If your IFRS 18 operating profit subtotal differs materially from the operating profit figure you currently report, analysts will notice. The first IFRS 18 filing will include a restated 2026 comparative, and if that comparative shows a different operating profit from what you reported in your 2026 earnings releases, you will need to explain the difference clearly.

Don't wait until the 2027 filing to have that conversation. Brief your key analysts and institutional investors in Q3 or Q4 2026, before the year-end close, with a clear explanation of what changes and why. Provide a bridge from the current operating profit definition to the IFRS 18 subtotal. This is also the moment to explain any MPM changes: measures you're retiring, measures you're retaining with tighter definitions, and what the new reconciliation note will show.

IR teams that treat this as a compliance footnote will face awkward analyst calls. IR teams that get ahead of it will find it's an opportunity to reset the performance narrative on cleaner terms.

Should You Consider Early Adoption?

Early adoption is permitted for periods beginning on or after the April 2024 issue date. For most entities, the practical barriers are significant: systems aren't ready, comparative data capture hasn't started, and the organisation hasn't been trained. But for entities that are already mid-way through a systems overhaul, or that are implementing IFRS S1/S2 simultaneously and want to align reporting timelines, early adoption deserves a serious look.

Note the IFRS S1/S2 interaction: companies implementing ISSB sustainability standards alongside IFRS 18 face competing demands on finance, IT, and IR teams through 2026. If your organisation is in this position, sequence the workstreams explicitly. Our IFRS S1 disclosure requirements walkthrough and IFRS S2 checklist cover those parallel obligations.

Judgments That Must Be Documented Before Filing

Auditors will expect written documentation of the following accounting judgments before they sign off on the first IFRS 18 financial statements. Build this documentation file in Phase 2 and update it through Phase 4.

• Definition of main business activity at the group level and at each subsidiary level where it differs
• Classification rationale for every P&L line item where the category assignment is non-obvious (foreign exchange differences, interest on trade receivables, gains on disposal of PP&E)
• MPM identification decisions: which measures were assessed, which were designated as MPMs, and which were retired and why
• Basis for the operating expense disaggregation in the notes, including any estimates used and why they are reliable
• Transition relief assessment: whether the impracticability relief was considered and, if not applied, why the data was obtainable

Leaving these judgments implicit is the single fastest way to extend your audit timeline in 2027.

FAQ

When does IFRS 18 take effect and when do we need to start capturing data? IFRS 18 is mandatory for annual periods beginning on or after 1 January 2027. Because retrospective application is required, entities with a 31 December year-end must capture and classify 2026 financial data under IFRS 18 from 1 January 2026. The data capture window is already open.

Does IFRS 18 change our profit or EPS figures? No. IFRS 18 is a presentation and disclosure standard. It doesn't change recognition or measurement, so total profit, EPS, and net assets are unaffected. What changes is how profit is analysed and where items appear in the income statement.

Which non-GAAP measures become MPMs under IFRS 18? Any subtotal of income and expenses that management communicates outside the financial statements (in earnings releases, investor presentations, or management commentary) and that isn't defined by IFRS Standards qualifies as an MPM. Adjusted EBITDA, underlying EBIT, and adjusted operating profit are the most common candidates. See our IFRS 18 MPM walkthrough for the full identification test.

Do subsidiaries need to change their own bookkeeping? Often yes. Where disaggregation of operating expenses or proper category classification can't be achieved through estimation or top-side entries, subsidiaries need to follow uniform account mapping and bookkeeping practices from the start of the comparative period.

What is the impracticability relief in the IFRS 18 transition provisions? The IASB confirmed that entities are not required to disclose the quantitative impact of applying IFRS 18 for the first time if that information is impracticable to obtain. This is a narrow relief and doesn't excuse the restatement of comparative income statement data itself.

Can we use our existing ERP without changes? It depends on your current chart of accounts and how granular your transaction coding is. Entities with a simple P&L structure may manage with a mapping overlay in their consolidation tool. Entities with complex subsidiary structures or significant operating expense disaggregation requirements will almost certainly need ERP configuration changes, which carry a 3-6 month minimum lead time.

The window to get this right is 2026. Teams that treat IFRS 18 as a 2027 problem will spend the first half of 2027 reconstructing data under audit pressure, renegotiating covenants in a hurry, and explaining unexpected operating profit movements to analysts who weren't briefed. The teams that mobilise now will file with confidence.