Stock: valuation: the valuation bases
Acceptable valuation bases
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  29TC387), see BIM33135,
- mark to market, see BIM33160.
All other bases are not acceptable for tax purposes.
Construction contracts are valued on a basis that brings in a profit/loss element, see BIM33025.
The valuation included in financial statements prepared in accordance with generally accepted accounting practice should be accepted provided that:
- it reflects the correct application of generally accepted accounting practice,
- the method pays sufficient regard to the facts,
- the basis does not violate the taxing statutes as interpreted by the courts.
Following the decisions in Ostime v Duple Motor Bodies Ltd  39TC537, and Threlfall v Jones  66TC77 the basis of valuation adopted in accounts should be accepted as valid for tax purposes.
Accurate provisions for foreseen losses on construction contracts made in accordance with generally accepted accounting practice are deductible for tax purposes following the decision in Herbert Smith v Honour  72TC130.
The need for the basis of valuation to reflect the actual facts was emphasised in Minister of National Revenue v Anaconda American Brass Co Ltd ,  2 WLR 31 (BIM33120)-. A valuation that pays insufficient attention to the facts will not be acceptable even if it is made on a recognised basis. In some circumstances there may be more than one acceptable method of computing the value of stock but the valuation policy should be consistent unless the reasons for change outweigh the need for consistency.
Alternative acceptable approaches
In some situations there may be two or more acceptable approaches to valuing work-in-progress. HMRC do not have the right to substitute one basis that is valid for tax purposes for another such basis. In Pearce v Woodall-Duckham Ltd  51TC271 for example Templeman J said:
‘the company was entitled to produce accounts based on its on- cost method prior to 1969. The company was entitled, but not bound, to produce accounts for 1969 and subsequent years by the accrued profit method. The change was made for sound commercial reasons.’
Equally the HMRC view is that where a basis which is valid for tax purposes has been adopted in a taxpayer’s accounts the taxpayer does not have the right to adopt a different basis in computing the profits figure to be entered on his tax return.
In Johnston v Britannia Airways Ltd  67TC99 Knox J said:
‘Which of the three ways in which the attribution of cost to a period or periods of accounting is adopted is, in my view, essentially a matter of accountancy judgement, and I am quite unable to detect any legal basis for excluding any of them.’
Although in that case the Special Commissioners had expressed a preference for the method actually adopted by the taxpayer, that was not the basis of their decision.