How do I account for stock and inventory for tax?
Answered 11 March 2026
Accounting for Stock and Inventory for Tax Purposes
What the law says
The statutory rules on trading stock are found in Chapter 12, Part 2 of ITTOIA 2005 (for income tax) and Chapter 11, Part 3 of CTA 2009 (for corporation tax). These provisions govern the valuation of trading stock, including appropriations, disposals, and acquisitions of stock.
Changes in trading stock (appropriations, things becoming stock, disposals, and acquisitions) are governed by sections 172B–172E of ITTOIA 2005 and the equivalent CTA 2009 provisions, with effect for changes occurring on or after 12 March 2008.
HMRC Guidance / Practice
1. What is "Stock" or "Inventory"?
Stock is anything acquired with a view to reselling at a profit. The term "inventory" is interchangeable with "stock" in accounts prepared under GAAP. Under UK GAAP (FRS 102), stock/inventory is classified as:
- Raw materials and consumables
- Work in progress
- Finished goods and goods for resale
- Payments on account
The relevant accounting standards are FRS 102 Section 13, FRS 105 Section 10, IAS 2, and (old UK GAAP) SSAP 9.
2. How Stock Feeds into Taxable Profits
Trading profits are computed as the difference between receipts and expenditure for the period. The values of opening and closing stock must be entered in the profit and loss account at cost or market price, whichever is the lower. This means:
- Opening stock is a deduction (cost of goods available)
- Closing stock is added back (reducing the cost charged)
3. Acceptable Valuation Bases
There are only two acceptable bases for valuing stock for tax purposes:
| Method | Description |
|---|---|
| Lower of cost or net realisable value (NRV) | The primary method; "NRV" under FRS 102 = estimated selling price less costs to complete |
| Mark to market | Acceptable in certain trades (e.g. financial trading) |
The valuation in financial statements prepared under GAAP should be accepted for tax purposes provided it: (a) reflects correct application of GAAP, (b) pays sufficient regard to the facts, and (c) does not violate the taxing statutes.
All other bases are not acceptable, including:
- LIFO (Last In, First Out) — expressly disallowed; it does not truly reflect profit for tax purposes
- Base stock method
- Notional replacement cost
Note: FIFO (First In, First Out) is an acceptable method of identifying cost under the lower of cost/NRV basis.
4. Stock Provisions (Write-Downs)
Where stock is impaired (e.g. slow-moving, obsolete, or defective), FRS 102 Section 27 requires the carrying amount to be reduced to selling price less costs to complete and sell — this is typically done via a stock provision.
Such provisions are allowable for tax purposes provided they:
- Relate to allowable revenue expenditure (not capital)
- Are in accordance with GAAP
- Do not conflict with any statutory timing rule
- Are estimated with sufficient accuracy
Formulae-based provisions (including age-related formulae) are acceptable provided each formula reflects a realistic appraisal of future income from the stock category and results in a reasonable estimate of NRV.
5. Consistency of Valuation Method
The valuation basis must be consistent from year to year. A change of basis is permitted only where the reasons for change outweigh the need for consistency. If you change basis, you must notify HMRC.
Where a change is made from an invalid to a valid basis, both opening and closing stock for the period of change must be computed on the new valid basis.
6. Penalties
"If tax is lost or delayed as a result of incorrect valuation of stock then interest and penalties may be due in addition to the tax."
Citation sources
The stock of a trade can be anything acquired with a view to reselling at a profit. The term ‘inventory’ is sometimes used as an alternative to the term ‘stock’ in accounts prepared in accordance with GAAP. The two terms are equivalent and interchangeable. In accounts prepared in accordance with UK GAAP (BIM31000) inventory (or stock) should be classified as: raw materials and consumables, work in progress (BIM33020), finished goods and goods for resale, payments on account. The guidance in this
A provision made in accounts is the recognition of a liability, the timing or amount of which is uncertain. Provisions are distinguished from trade payables and accruals and are reported separately in accounts. The word ‘provision’ is also often used to refer to the recognition of a reduction in the carrying amount of an asset, for example, a debt impairment provision or an inventory (stock) provision. The rules governing such ‘provisions’, both in accountancy practice and tax law, are differen
The guidance in this chapter includes not only information on the acceptable valuation bases but also some descriptive paragraphs to give a feel for the important factors in a stock valuation. Stock valuation can never be absolutely precise, with a number of practical considerations affecting the accuracy of the estimate. GAAP provides the starting point for stock valuation for tax purposes, but you should note that it does not always prohibit methods such as last in first out (LIFO) for costing
The basis may be invalid because it does not follow generally accepted accounting practice or because it pays so little attention to the facts that it is not reflecting cost or net realisable value. In the accounting period when the basis of stock valuation is changed from an invalid basis to a valid basis both the opening stock valuation and the closing stock valuation must be computed on the new valid basis. Where it is possible to re-open or amend earlier years (using discovery powers) the op
When a business ceases to trade, it may still have trading stock which needs to be sold. If the trading stock is valued in accordance with the tax legislation and included in the profit and loss account in the final period of account, any amount received for the transfer of the stock is not a post-cessation receipt. This is because the value of the trading stock has already been included in calculating the taxable profits of the trade to cessation. The rules on valuation of stock on cessation ar
lief for the expected loss may be obtained in the period for which the accounts are being prepared by valuing the stock at what it is expected to realise when sold in the normal course of trade. For tax purposes we are looking for a figure (commonly referred to as a valuation) which represents the cost, or, if lower, the net realisable value of the stock. In some circumstances there may be more than one acceptable method of computing the value of stock but the basis of valuation in a particular
uing stock for tax purposes. This decision was not upheld by the Courts in Canada and came on appeal to the Privy Council. Viscount Simonds said: The income tax law of Canada, as of the United Kingdom, is built upon the foundations described by Lord Clyde in Whimster & Co v CIR [1925] 12TC813, in a passage cited by the Chief Justice which may be here repeated. “In the first place, the profits of any particular year or accounting period must be taken to consist of the difference between the recei
Part 2 Income tax, corporation tax and capital gains tax_general Other business and investment measures Trade profits: changes in trading stock 37 1 Schedule 15 contains provision about the effect of certain changes in trading stock on the calculation of profits of trades for the purposes of income tax or corporation tax. 2 The amendments made by that Schedule have effect in relation to changes in trading stock occurring on or after 12 March 2008. 3 In subsection (2) “ change in trading stock ”
There are two acceptable valuation bases for stock and work in progress as follows: the lower of cost or net realisable value (CIR v Cock Russell & Co Ltd [1949] 29TC387), see BIM33135, mark to market, see BIM33160. ‘Net realisable value’ is a term used in old UK GAAP and IAS. FRS 102 and FRS 105 use the equivalent term ‘estimated selling price less costs to complete’. All other bases are not acceptable for tax purposes. Construction contracts are valued on a basis that brings in a profit/loss e
All bases of stock valuation other than the lower of cost and net realisable value and mark to market are not acceptable for the purposes of Income Tax or Corporation Tax on trade profits. The notional replacement cost method (that is, a notional price at which the trader would have to buy stock in order to realise the normal rate of profit), BSC Footwear Ltd v Ridgeway [1971] 47 TC 495 is not acceptable but see BIM33135 for a description of an acceptable replacement cost method. Following Patri
FRS 102 Section 27 Impairment of Assets Paragraph 27.2 states that an entity shall assess at each reporting date wither any inventories (stocks) are impaired by comparing the estimated selling price less costs to complete to the current carrying amount. If inventory is impaired, the entity shall reduce the carrying amount of the inventory to its selling price less costs to complete and sell. This will typically involve the entity booking a stock provision. The calculation of a stock provision re
Provisions and write downs arrived at using formulae, including age related formulae, are acceptable provided that each formula reflects a realistic appraisal of the future income from the particular category of stock and results in the stock being included at a reasonable estimate of its net realisable value. Pinpoint accuracy cannot be achieved but the assumptions made should be realistic. After reviewing the position in a particular case an Inspector may agree that certain formulae are approp