The Most Important IFRS and IAS Standards Every Finance Professional Should Know

If you work in finance, accounting, audit or investment analysis, IFRS and IAS are the rules of the game. They define when revenue is recognised, how an asset is measured, which liabilities are recorded, and what gets disclosed in the notes. They are not academic trivia — they are what sits behind every number in a set of audited accounts.

This guide covers the standards that, in practice, move the financial statements of most non-financial businesses. It is meant as a refresher, or a mental map if you are coming in from a different background.

IFRS vs IAS: What Is the Difference?

IAS (International Accounting Standards) are the standards issued by the old IASC between 1973 and 2001. IFRS (International Financial Reporting Standards) are the standards issued by the IASB from 2001 onwards. Both are mandatory under the IFRS framework: when an IFRS replaces an IAS, the older one is withdrawn; the IAS standards still in force (such as IAS 1, IAS 16, IAS 36) are just as binding as any IFRS.

Over 140 jurisdictions either require or permit IFRS. The United States still uses US GAAP, but the underlying concepts overlap heavily.

IAS 1 — Presentation of Financial Statements

The starting point. IAS 1 defines what a complete set of financial statements looks like: balance sheet, income statement, statement of changes in equity, statement of cash flows and notes. It sets the fundamental principles: going concern, accrual basis, materiality, offsetting, frequency, comparability.

If you have ever wondered why current and non-current liabilities are split, or why exceptional items are presented where they are, the answer is here.

IAS 7 — Statement of Cash Flows

Defines the structure of the cash flow statement in three blocks: operating, investing and financing activities. Permits direct or indirect method (in practice almost everyone uses indirect). It is the standard that links accounting profit to actual cash.

IAS 2 — Inventories

Inventories are measured at the lower of cost and net realisable value. Cost includes purchase, conversion and other costs incurred in bringing the inventories to their present location and condition. FIFO and weighted average are permitted; LIFO is prohibited under IFRS (a classic difference vs US GAAP).

IAS 16 — Property, Plant and Equipment

Covers the recognition, initial and subsequent measurement, depreciation and derecognition of tangible fixed assets. Two post-recognition models: cost or revaluation. Depreciation should reflect the pattern in which the asset's economic benefits are consumed — useful life, residual value and method are reviewed annually.

IAS 38 — Intangible Assets

To recognise an intangible you need three things: identifiability, control and probable future economic benefits. R&D spend is treated asymmetrically: research is expensed; development is capitalised if six criteria are met. Internally generated goodwill is never capitalised.

IAS 36 — Impairment of Assets

One of the most consequential standards at a macro level because it determines when big impairments hit and ruin a quarter. An asset is impaired when its carrying amount exceeds its recoverable amount (the higher of fair value less costs of disposal and value in use). Goodwill and indefinite-life intangibles are tested annually; everything else only when there are indicators.

IAS 37 — Provisions, Contingent Liabilities and Contingent Assets

A provision is only recognised when there is a present obligation (legal or constructive) as a result of a past event, an outflow is probable, and the amount can be reliably estimated. Contingent liabilities are only disclosed in the notes. This is the standard governing warranties, litigation, restructurings and decommissioning.

IAS 12 — Income Taxes

Covers both current and deferred tax. Deferred tax arises from temporary differences between the carrying amount and the tax base of assets and liabilities. Carried-forward tax losses can generate deferred tax assets — but only if it is probable that future profits will exist against which they can be utilised. That last condition is where most of the judgement lives.

IAS 19 — Employee Benefits

The pensions standard. Distinguishes between defined contribution plans (employee bears the risk) and defined benefit plans (employer bears the risk, which can create enormous balance sheet liabilities). At UK and European companies with legacy DB schemes, this standard can move hundreds of millions of pounds on changes in the discount rate alone.

IAS 21 — The Effects of Changes in Foreign Exchange Rates

Defines functional currency, presentation currency, and how transactions and the financial statements of foreign subsidiaries are translated. Exchange differences on monetary items go to P&L; differences from translating foreign subsidiaries go to OCI (other comprehensive income).

IFRS 15 — Revenue from Contracts with Customers

The single biggest revenue recognition change of the past decade. It introduced a five-step model:

• 1.Identify the contract with the customer
• 2.Identify the separate performance obligations
• 3.Determine the transaction price
• 4.Allocate the transaction price to each performance obligation
• 5.Recognise revenue when (or as) each obligation is satisfied

It particularly affects software, telecoms, construction, engineering and any business with subscription or multi-year contract models.

IFRS 16 — Leases

The other big recent change. It killed the operating vs finance lease distinction for the lessee: today almost all rental contracts are recognised on the balance sheet as a right-of-use asset and a lease liability. This inflated the balance sheets of retailers, airlines and anyone with a lot of rented shops or offices.

It also distorted comparatives: EBITDA tends to rise (rent expense moves out), while net debt and assets go up. Worth bearing in mind when comparing companies across the transition (pre-2019 vs post-2019).

IFRS 9 — Financial Instruments

Replaced IAS 39. Three main blocks: classification and measurement of financial assets (amortised cost, FVOCI, FVTPL), impairment via an expected credit loss (ECL) model, and hedge accounting. For banks, IFRS 9 is the standard that moves the bottom line most: the ECL model forces provisioning for expected losses before they happen.

IFRS 3 — Business Combinations and IFRS 10 — Consolidated Financial Statements

The two standards governing acquisitions and consolidation. IFRS 3 mandates the acquisition method: acquired assets and liabilities are recognised at fair value, and the excess of consideration paid over the fair value of net assets is goodwill. IFRS 10 defines control: power, exposure to variable returns and the ability to affect those returns.

IFRS 13 — Fair Value Measurement

Defines how to measure fair value when another standard requires it. Introduces the three-level hierarchy: Level 1 (quoted prices in active markets), Level 2 (observable inputs other than Level 1), Level 3 (unobservable inputs, model-based valuation). The Level 1/2/3 split in the notes is one of the first things a credit analyst looks at on a bank.

Quick Reference Table

How to Use This List in Practice

No analyst or finance director memorises IFRS word for word — what they do is know which standard applies to which problem, and where to find the detail. When you read a set of accounts, identify the relevant accounting policies first (usually in note 2 or 3) and the areas of judgement (impairment, deferred tax, provisions, revenue). That is where the risk sits and where the surprises come from.

Three rules of thumb: always read the accounting policies note, never assume comparability without checking (especially across IFRS 15 and IFRS 16), and never trust EBITDA before checking what sits beneath it.