［Concept 061］HKAS 12 / IAS 12 in Plain English: A Full Walkthrough of Deferred Tax and the Balance Sheet Liability Method

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Plain‑English explainer of HKAS 12 / IAS 12 for students, junior accountants and non‑specialists who find official standards too dense to read.

This article is based on Hong Kong Accounting Standards (HKAS / HKFRS), which are fully aligned with IAS / IFRS except for minor local tweaks, so the same principles generally apply under IAS / IFRS unless noted otherwise. The goal is to unpack HKAS 12 Income Taxes (equivalent to IAS 12) using plain English and practical, real‑life examples instead of technical jargon. It is written for students, junior accountants, audit juniors and finance professionals who want to understand not just “what the standard says” but how to actually read and prepare financial statements in line with it.

When you see “the company” or “the entity” below, you can think of any entity that prepares general purpose financial statements under HKFRS / IFRS.

Why Should You Care About HKAS 12?

Many people’s first “encounter” with HKAS 12 happens when they read a listed company’s annual report. In the statement of profit or loss, there is only one line called “income tax expense”. But when you turn to the notes, you suddenly see a whole page of terms: current tax, deferred tax, temporary differences, unused tax losses and so on.

At the same time, your audit working papers ask for an effective tax rate reconciliation. Colleagues who are new to tax accounting often ask the same questions:

• Why do we even have deferred tax?
• What do all these numbers actually represent?

The role of HKAS 12 / IAS 12 is to provide a consistent “language” for reporting income taxes in financial statements, including both:

• Current tax for this period, and
• Expected future tax effects of past transactions (deferred tax).

For students and junior staff, once you understand the objective of HKAS 12, the basic split between current tax and deferred tax, and the balance sheet liability method, you have already taken the first step toward making sense of income tax accounting.

What You Should Be Able To Do After Reading?

By the end, you should be able to:

• Explain, in one sentence, what problem HKAS 12 / IAS 12 is trying to solve and broadly what types of taxes and situations it covers.
• Distinguish clearly between “current income tax” and “deferred tax”, and use a simple numerical example to calculate current tax expense and tax payable (or tax receivable).
• Use the balance sheet liability method formula: Carrying amount − Tax base = Temporary difference Temporary difference × Tax rate = Deferred tax to understand the logic behind deferred tax liabilities and deferred tax assets.
• Explain what “tax base” means and roughly determine the tax base for common items such as property, plant and equipment, deferred revenue and provisions.
• When you see depreciation timing differences, warranty provisions, fair value adjustments or unused tax losses, you can at least recognise that there may be taxable or deductible temporary differences and know that you should investigate further.

1. Objective and Scope of HKAS 12 / IAS 12

The Overall Objective

From a high level, HKAS 12 Income Taxes (equivalent to IAS 12) has a very simple objective:

to prescribe how an entity should account for income taxes, so that the financial statements reflect both the current and future tax consequences of past transactions and events.

Here, “income taxes” includes:

• Taxes that are already due based on current taxable profit (current tax).
• Taxes that will arise in the future because of differences between accounting and tax treatment of past transactions (deferred tax).

What Counts as “Income Tax”?

HKAS 12 defines income taxes as all domestic and foreign taxes that are based on taxable profit. This includes, for example:

• Hong Kong profits tax.
• PRC corporate income tax.
• Corporate income taxes in other jurisdictions.
• Withholding taxes, such as tax withheld on overseas dividends.

Key points:

• The tax must be based on some measure of profit, not simply gross revenue or asset value.
• As long as the tax is computed on taxable profit, it generally falls within the scope of HKAS 12 / IAS 12.
• Withholding tax on income like dividends is also treated as income tax for accounting purposes under this standard.

By contrast, if a tax is based on:

• Turnover or gross receipts (e.g. some sales taxes),
• Asset values (e.g. some types of property taxes), or
• Transaction amounts,

then it is usually outside HKAS 12. Such taxes are generally treated as operating expenses or handled under other standards rather than as income tax in the HKAS 12 sense.

Where HKAS 12 Sits in the Standards Framework

HKAS 12 / IAS 12 does not stand alone. It interacts with other standards to complete the picture of the financial statements.

Examples:

• The line “income tax expense” in the statement of profit or loss (and OCI) is broken down and classified using principles from HKAS 12.
• When assets are revalued at fair value under standards like HKAS 16 Property, Plant and Equipment or HKFRS 9 Financial Instruments, and the fair value gain is not taxed immediately, HKAS 12 guides how to recognise the related deferred tax.
• When a transaction is recognised directly in equity or in other comprehensive income (e.g. certain revaluation reserves or FVOCI movements), the related tax effects should also be recognised in the same channel (equity or OCI) under HKAS 12.

Once you understand this positioning, you know that whenever you want to understand “what is going on with tax” in the financial statements, HKAS 12 / IAS 12 is the standard you go back to.

2. Current Tax: Recognition and Measurement

Before tackling deferred tax, it helps to make sure current tax is solid.

What Is Current Income Tax?

Current income tax is the amount of income taxes payable (or recoverable) in respect of the taxable profit (or tax loss) for the current period, plus any adjustments for prior periods.

In simple terms, for the current year:

• The entity calculates taxable profit according to the relevant tax laws.
• It then applies the applicable tax rate to determine the tax payable.
• That amount, together with prior-year adjustments, is recognised as current tax expense and as a tax liability (or asset).

In the financial statements:

• Profit or loss: current tax expense forms part of “income tax expense”.
• Balance sheet:
  • Income tax payable: unpaid tax at the reporting date.
  • Income tax receivable: tax already paid that is expected to be refunded or offset in the future.

HKAS 12 follows the accrual basis: recognise current tax when it is incurred, not when cash is actually paid or refunded.

Measurement Principles and Tax Rates

For current tax, HKAS 12 / IAS 12 requires using tax rates and tax laws that have been enacted or substantively enacted by the end of the reporting period.

This means:

• If a tax rate change has been passed into law (or is substantively enacted) before the reporting date, you use that rate even if it is only effective in a future period.
• If a new regime is highly likely to become law (substantively enacted), entities reflect that in current tax measurements as well.

Simple Example

Assume:

• The company’s taxable profit for the year is HK$1,000,000.
• The applicable profits tax rate is 16.5%.
• There are no major tax disputes or special adjustments.

Then:

• Current income tax expense = 1,000,000 × 16.5% = 165,000.

If by year end the company has not paid any profits tax:

• Balance sheet: income tax payable = 165,000.
• Profit or loss: income tax expense (current tax) = 165,000.

If the company had prepaid HK$100,000 of tax during the year:

• Remaining income tax payable = 65,000 (165,000 − 100,000).
• If prepayments exceeded the final tax due, the excess would be presented as an income tax receivable (current tax asset).

In practice, the complexity in current tax often comes from:

• Tax adjustments such as non-deductible expenses, different tax depreciation rules, and specific incentives. But the core idea remains:
• Start from accounting profit.
• Adjust to taxable profit using enacted or substantively enacted tax laws.
• Apply the tax rate to get current tax payable or receivable.

3. The Balance Sheet Liability Method and Temporary Differences

The key to understanding deferred tax is to change your question.

Instead of asking:

• “Is there tax on this item now?”

Ask:

• “When this asset is recovered or this liability is settled, will the tax I pay in the future be higher or lower because of how this item is recorded today?”

This is the mindset behind the balance sheet liability method.

The Core Formula

HKAS 12 / IAS 12 adopts the balance sheet liability method. In a compressed form, the logic is:

Carrying amount − Tax base = Temporary difference

Temporary difference × Applicable tax rate = Deferred tax (asset or liability)

Where:

• Carrying amount: the amount of an asset or liability in the statement of financial position.
• Tax base: the amount attributed to that asset or liability for tax purposes under the tax law.
• Temporary difference: the difference between carrying amount and tax base that will result in taxable or deductible amounts when the asset is recovered or the liability is settled.

Taxable vs Deductible Temporary Differences

Temporary differences fall into two main categories:

• Taxable temporary differences These will result in taxable amounts in future periods when the asset is recovered or the liability is settled. They typically give rise to deferred tax liabilities (DTLs).
• Deductible temporary differences These will result in amounts that are deductible in future periods, reducing future taxable profit (or increasing future tax losses). They can give rise to deferred tax assets (DTAs), but only to the extent that it is probable that future taxable profit will be available.

A very common situation is:

• Accounting depreciation is on a straight-line basis.
• Tax depreciation is accelerated (larger deductions in early years).

In the early years:

• Tax depreciation > accounting depreciation → taxable profit is lower now, higher later. From the balance sheet perspective:
• The carrying amount of the asset and its tax base start to diverge.
• This difference is a taxable temporary difference, which normally leads to a DTL.

Temporary Differences vs Permanent Differences

Temporary differences are often confused with permanent differences.

• Temporary differences:
  • Arise because accounting and tax values of assets or liabilities differ.
  • Will reverse over time as the asset is recovered or the liability is settled.
  • Create deferred tax (DTL or DTA).
• Permanent differences:
  • Certain income or expenses are never taxable or never deductible.
  • They do not reverse in future periods.
  • They do not give rise to deferred tax.

Examples of permanent differences:

• Non-deductible penalties or fines.
• Certain tax-exempt interest income (e.g. on specific government bonds in some jurisdictions).
• Expenses that will never be recognised for tax purposes.

These items affect the relationship between accounting profit and tax expense in the current period and therefore impact the effective tax rate reconciliation. But because they never reverse, they do not create temporary differences and therefore do not create deferred tax.

When you read the income tax note and see a line called “permanent differences” in the effective tax rate reconciliation, that line is exactly explaining these non-reversing items.

4. Tax Base: Definition and How to Think About It

To apply the balance sheet liability method, you must understand the tax base. HKAS 12 / IAS 12 defines tax base as the amount attributed to an asset or liability for tax purposes, which will be deductible or taxable when the asset is recovered or the liability is settled.

Tax Base of Assets: Amount Deductible on Recovery

For an asset, the tax base is usually the amount that will be deductible for tax purposes against future taxable economic benefits when the asset is recovered (through use or sale).

If the future recovery of an asset will not give rise to taxable income, the tax base of that asset is equal to its carrying amount.

Let’s anchor this with common scenarios.

(a) Property, Plant and Equipment

Assume:

• A machine has a carrying amount of 800.
• For tax purposes, there is still 500 of tax depreciation left to deduct (tax base = 500).

Then:

• Carrying amount 800 − Tax base 500 = 300 taxable temporary difference.
• This typically leads to a deferred tax liability.

(b) Financial Assets at Fair Value through OCI (FVOCI)

Under HKFRS 9 / IFRS 9, some financial assets are measured at fair value with changes in fair value recognised in other comprehensive income. Suppose:

• The fair value of an investment increases by 200 and this increase is recognised in OCI.
• For tax, that 200 gain is not taxed until the investment is sold.

Then:

• The tax base remains at original cost.
• The difference between carrying amount (fair value) and tax base (cost) is a taxable temporary difference.
• A deferred tax liability arises and, because the gain went to OCI, the related deferred tax is also recognised in OCI.

(c) Trade Receivables

In many cases, the tax base of trade receivables equals their carrying amount, because the related revenue has already been included in taxable profit and taxed.

Usually:

• No additional taxable or deductible amounts arise on collection.
• Therefore, no temporary difference is created, unless there is a timing difference related to impairment losses or bad debt allowances that are treated differently for tax purposes.

Tax Base of Liabilities: Future Deductible Amounts

For a liability, the tax base is its carrying amount minus any amounts that will be deductible for tax purposes in future periods when the liability is settled.

If settlement of a liability will not lead to any tax deduction in the future, then the tax base equals the carrying amount.

Common examples:

(a) Deferred Revenue / Contract Liabilities

Assume:

• The entity receives 1,000 in cash but has only recognised part of the revenue in accounting; the rest is recorded as deferred revenue (a liability).
• For tax purposes, the full 1,000 has already been taxed when the cash was received.

In the future, when the entity performs the service:

• Accounting will recognise revenue, but tax will not tax it again.

From a tax base perspective:

• The liability often has a tax base lower than its carrying amount (or even zero), because tax law has already taxed it and will not grant any further deduction when the liability is settled.
• This situation commonly gives rise to a deductible temporary difference and therefore a deferred tax asset, because when the liability is settled, taxable profit will be lower than accounting profit.

(b) Provisions (e.g. Warranty Provisions)

Assume:

• The entity recognises a warranty provision of 500 in accounting when the product is sold.
• For tax purposes, the expense is only deductible when the actual repair costs are incurred in the future.

Typically:

• The tax base of the liability is its carrying amount minus the amounts that will be deductible in the future. In many cases, this is initially zero.
• That means the carrying amount of the liability is greater than its tax base, creating a deductible temporary difference.
• This leads to a deferred tax asset, provided that it is probable that the entity will have sufficient future taxable profit for the deduction to be used.

The key question you should always ask is:

When this liability is settled, what tax deduction (if any) will I get?

Only then do you plug the numbers into the formula:

• Carrying amount − Tax base = temporary difference.

5. Typical Sources of Temporary Differences

Once you are comfortable with “carrying amount vs tax base”, you can start scanning your daily work for common patterns. HKAS 12 / IAS 12 often highlights the following as typical sources of temporary differences:

Depreciation Timing Differences

• Accounting: straight-line depreciation.
• Tax: accelerated depreciation or different tax allowances.

Early years:

• Tax depreciation > accounting depreciation → taxable profit is lower now, higher later.

From the balance sheet viewpoint:

• Carrying amount of PPE > tax base.
• This creates a taxable temporary difference → deferred tax liability.

Development / Research Costs

• Accounting may capitalise certain development costs if criteria are met.
• Tax rules may allow immediate deduction or deductions over a different period.

This creates differences between:

• Carrying amount of the development asset, and
• Tax base (amount still deductible for tax).

Depending on the tax treatment:

• The difference may be taxable or deductible.
• Hence, it can give rise to either a DTL or a DTA.

Warranty Provisions and Other Provisions

• Accounting recognises a provision upfront (e.g. warranty costs or restructuring).
• Tax often allows deduction only when the expenditure is actually incurred.

Result:

• Carrying amount of the liability > tax base (often zero initially).
• This is a deductible temporary difference.
• It may give rise to a deferred tax asset, provided the “probable future taxable profit” test is met.

Fair Value Adjustments on Financial Assets

• Financial assets are measured at fair value with changes recognised either in profit or loss or in OCI.
• Tax law in many jurisdictions taxes gains only when they are realised (e.g. on disposal).

So:

• Carrying amount of the asset reflects fair value.
• Tax base may remain at original cost.

This difference is typically a taxable temporary difference:

• It often leads to a deferred tax liability, recognised in profit or loss or OCI consistent with where the underlying gain or loss is recorded.

Unused Tax Losses and Tax Credits

If the entity has:

• Tax losses carried forward, or
• Unused tax credits that can offset future taxable profits,

HKAS 12 / IAS 12 treats these as a kind of deductible temporary difference.

They may give rise to a deferred tax asset, but only if:

• It is probable that there will be sufficient future taxable profit to utilise them.

If an entity has suffered recent or ongoing losses:

• The standard requires a more cautious assessment.
• Often, “convincing other evidence” is needed to justify recognising a deferred tax asset, such as firm forecasts or the existence of sufficient taxable temporary differences that will reverse in the right periods.

For beginners, the key here is not to memorise every rule, but to build a habit:

• Whenever you see these types of transactions or balances, ask yourself: “Is there a difference between carrying amount and tax base that will affect future tax?” If yes, you are probably in deferred tax territory.

6. Why “Recovery of Assets / Settlement of Liabilities” Is the Foundation

To really internalise the idea of carrying amount vs tax base, you should not stop at the formula. The deeper intuition is this:

Every asset will eventually be recovered. Every liability will eventually be settled. At that moment, accounting and tax may recognise different amounts, and that difference turns into extra or reduced tax.

How the Difference Is “Realised” for Assets

Take PPE as an example:

• Accounting may spread the cost evenly through straight-line depreciation.
• Tax may allow big deductions upfront (accelerated allowances).

Early years:

• Tax depreciation is high, taxable profit is lower, and you “seem” to save tax.

Later years:

• Accounting still has depreciation.
• Tax depreciation may already be fully used, so no more tax deduction.
• Taxable profit becomes higher than accounting profit.

In other words:

• The “tax saved” earlier is effectively paid back later.
• The mechanism that tracks this is the taxable temporary difference and the related deferred tax liability.

The recovery of the asset over its life is the process through which the difference between carrying amount and tax base gradually turns into actual tax cash flows.

How the Difference Is “Realised” for Liabilities

For liabilities, the logic is similar but reversed.

Take a warranty provision:

• Accounting recognises an expense and a liability in the year of sale.
• Tax allows deduction only when actual repair costs are incurred.

Year of sale:

• Accounting profit is lower (because of the provision).
• Taxable profit is higher (no deduction yet).
• It feels like you paid more tax now.

Later, when repairs are done and the liability is settled:

• Accounting simply reduces the provision; there may be little or no new expense.
• Tax finally allows deduction of the repair costs.
• Taxable profit is lower, so you “get back” some of the tax you paid earlier.

This is exactly how settlement of the liability transforms the difference between carrying amount and tax base into a real tax saving over time, which is what a deferred tax asset is trying to capture.

Why the Formula Matters

So the formula:

Carrying amount − Tax base = Temporary difference

is important not because it looks neat, but because it measures something very concrete:

If this asset were fully used or sold tomorrow, or this liability were fully settled tomorrow, how different would taxable profit be compared with accounting profit at that moment, purely due to today’s difference between carrying amount and tax base?

Once you see that:

• It becomes natural that HKAS 12 / IAS 12 starts from the balance sheet, identifies these differences, and then works out deferred tax from there.

7. Turning HKAS 12 into a Simple Four-Step “Mechanical” Logic

A common trap when learning HKAS 12 / IAS 12 is to get lost in terminology and examples, and forget that the standard is really answering just one question:

“Will this asset or liability cause me to pay more or less tax in the future?”

Here is a simple four-step mechanical way to approach any item. You can use this both in exams and in real working papers.

Step 1: Identify the Item – Asset or Liability? What Is the Tax Base?

When you see any balance sheet item, do not jump straight to “DTL or DTA”. Instead, ask:

• Is this an asset or a liability?
• Under the tax rules, what is its tax base (if any)?

For assets, think:

• “When I recover this asset (use or sell it), will tax let me deduct anything?”

For liabilities, think:

• “When I settle this liability, will tax give me a deduction?”

Once you have a clear picture here, many temporary differences reveal themselves quite naturally.

Step 2: Compare Carrying Amount and Tax Base – Don’t Label Yet

Only after Step 1 do you look at the numbers:

• Is the carrying amount greater than the tax base?
• Or is the carrying amount less than the tax base?

You can even give yourself a quick code:

• Carrying amount > tax base → “book bigger than tax”.
• Carrying amount < tax base → “book smaller than tax”.

At this stage, you are just observing the size and direction of the gap between accounting and tax. No need to worry about whether it is “taxable” or “deductible” yet.

Step 3: Imagine the Future Moment – More Tax or Less Tax?

Now ask the core HKAS 12 / IAS 12 question:

If this asset were recovered or this liability were settled in the future, would taxable profit at that time be higher or lower because of the current gap between carrying amount and tax base?

In practice, this means:

• If carrying amount > tax base, it often implies that future taxable profit will be higher (you will pay more tax later).
• If carrying amount < tax base, it often implies that future taxable profit will be lower (you will save tax later).

You do not need to remember every rule yet. You just need to be clear:

• “Will I pay extra tax in the future?” or
• “Will I save tax in the future?”

Once you know “extra” vs “save”, you are already standing at the door of temporary differences.

Step 4: Attach the HKAS 12 Labels – Taxable / Deductible, DTL / DTA

Only after Step 3 do you put the labels on:

• If you expect to pay more tax in the future:
  • You have a taxable temporary difference.
  • This normally leads to a deferred tax liability (DTL).
• If you expect to save tax in the future:
  • You have a deductible temporary difference.
  • This may give you a deferred tax asset (DTA), but you still need to check whether there will be enough future taxable profit to use it.

The whole point of this sequence is to push “terminology” to the last step, and focus first on the economics:

• Asset vs liability
• Carrying amount vs tax base
• Future extra tax vs future tax saving

Every time you apply these four steps to a new scenario, you are reinforcing the same mechanical logic rather than memorising isolated rules.

Conclusion: Turning HKAS 12 into a Daily Thinking Tool

The goal of mastering HKAS 12 / IAS 12 is not to memorise definitions for exams. It is to build a stable thinking framework that you can use whenever you deal with transactions or read financial statements.

Next time you face a transaction or prepare a balance sheet working paper, try asking yourself:

• What is the carrying amount of this asset or liability? What is its tax base under the relevant tax law? Is there a difference between the two?
• If there is a difference, when the asset is recovered or the liability is settled, will taxable profit be higher or lower? Is that a taxable temporary difference or a deductible temporary difference?
• Is this difference only a timing issue (temporary), or is it something that will never appear in tax at all (permanent)?
• If it is a deductible temporary difference, is it really probable that the entity will have enough future taxable profit to justify recognising a deferred tax asset?

For accountants and auditors in practice, a useful habit is:

• In your working papers, add one or two lines explaining each deferred tax balance:
  • What type of temporary difference it comes from.
  • How you determined the tax base.

This makes future reviews easier and also helps you reinforce your own understanding.

When reading financial statements, pay deliberate attention to:

• The deferred tax note with its breakdown by type of temporary difference.
• The effective tax rate reconciliation, which separates temporary differences from permanent differences.

Over time, HKAS 12 / IAS 12 will stop feeling like an abstract “tax theory” standard, and instead become a practical tool you use every day to understand an entity’s tax position and how today’s accounting choices affect tomorrow’s tax.

Key takeaways for students and junior accountants

• Always start with the balance sheet: for any item, write down its carrying amount and its tax base under the relevant tax law; the gap between the two is where temporary differences live.
• Do not jump straight to labels like “DTL” or “DTA”; first ask whether, on recovery/settlement, taxable profit will be higher (more tax) or lower (tax saving) because of today’s difference.
• Train yourself to “scan” for classic deferred tax triggers in your files: depreciation timing differences, provisions (especially warranties), fair value movements and unused tax losses or credits.
• When you see a deductible temporary difference, remember it does not automatically mean a deferred tax asset; you still need evidence that there will be sufficient future taxable profit to use it.
• In working papers, add one or two short explanation lines for each deferred tax balance (what transaction created the temporary difference, what tax base you assumed, and why it leads to DTL or DTA) to make reviews easier and to reinforce your own understanding.
• When reading financial statements, pay special attention to the deferred tax note and the effective tax rate reconciliation, and consciously separate in your mind what comes from temporary differences versus what comes from permanent differences.

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