What is IFRS 18 and why should group accountants care?

IFRS 18 'Presentation and Disclosure in Financial Statements' replaces IAS 1, effective for periods beginning 1 January 2027 (with comparatives, so transition work starts earlier). Three big changes. First, it mandates defined categories in the income statement — operating, investing, and financing — and requires new defined subtotals, notably 'operating profit', bringing comparability to a previously free-form P&L. Second, it regulates management-defined performance measures (MPMs) — non-GAAP/alternative metrics management uses publicly — requiring them to be disclosed in a single note, reconciled to the nearest IFRS subtotal, with explanations, ending the prior wild-west of adjusted measures. Third, it raises the bar on aggregation/disaggregation (grouping items by shared characteristics, more useful line items and note detail). For group accountants the impact is practical and significant: reporting packages and the consolidation system need redesign, the chart of accounts may be restructured to map to the new categories, MPMs need governance and reconciliation, and the transition year needs dual presentation. It's a presentation overhaul, not a recognition/measurement change.