Trading stock valuation is one of those areas of tax compliance that many small business clients don't think about until the accountant asks for the stocktake figures at year-end — and then the answer is sometimes a shrug. Getting trading stock valuation right matters both for tax accuracy and for financial statement integrity. The ATO has clear rules, and the choice of valuation method has real tax consequences.
What Is Trading Stock Under Australian Tax Law?
Under Division 70 of the Income Tax Assessment Act 1997, trading stock includes anything that is:
- On hand at the beginning or end of the income year
- Held by the business for the purpose of manufacture, sale, or exchange in the ordinary course of business
Trading stock explicitly excludes financial instruments (shares, bonds), real property held as an investment, and services. It includes raw materials, work-in-progress, and finished goods for product-based businesses, and items held for re-sale by retailers and wholesalers.
The significance of trading stock for tax purposes is this: the difference between opening and closing stock value is included in assessable income or is deductible. If closing stock is worth more than opening stock, the excess is added to income. If closing stock is worth less (stock has been sold, consumed, or written down), the decrease reduces income.
This means that the method used to value closing stock directly affects the tax result for the year.
The Three Valuation Methods: Section 70-45 Election
Section 70-45 of ITAA 1997 allows a taxpayer to value each item of trading stock at the end of each income year at one of three values:
- Cost
- Market selling value
- Replacement value
Importantly, the election is made on a per-item basis each year — different items can use different methods in the same year, and the method used for a particular item can change from year to year. This flexibility is significant and often underutilised.
Within the "cost" method, two approaches apply in practice:
FIFO (First In, First Out)
Under FIFO, the cost of closing stock is calculated as if the most recently purchased items are still on hand — the oldest (first purchased) items are assumed to have been sold first. In a period of rising prices, FIFO produces a higher closing stock value and therefore a higher taxable income compared to other methods, because the older (cheaper) stock has been "sold" and the newer (more expensive) stock remains on hand.
FIFO is appropriate where inventory genuinely turns over in the order it was acquired — perishable goods, time-sensitive products, and businesses where the physical flow of stock matches the FIFO assumption.
Average Cost (Weighted Average)
Under the weighted average cost method, all units of a particular item are assigned a uniform cost based on the weighted average of all purchases during the period. As new stock is purchased at different prices, the average cost is recalculated.
Average cost tends to smooth the effect of price fluctuations between FIFO and LIFO (LIFO is not permitted under Australian tax law or AASB 102). For businesses with high purchase volumes and frequent price changes — commodity-based businesses, hardware suppliers — average cost can produce a more stable tax result than FIFO.
Market Selling Value and Replacement Value
These two methods are alternatives to cost and can be elected for individual items independently of how other items are valued.
Market selling value is the price at which the item could be sold in the ordinary course of business — not a distressed or fire-sale price, but the normal market price. This method is most useful when stock has become obsolete, damaged, or out of season, and its market value has fallen below cost. Electing market selling value for these items effectively creates a deductible write-down without the need to dispose of the stock.
Replacement value is the cost to replace the item with an equivalent item at year-end. In periods of rising prices, replacement value will be higher than cost, producing a higher closing stock value. This method is less commonly used but may apply where the cost of replacing existing stock has increased significantly and the business wants its balance sheet to reflect current replacement costs.
The Small Business Trading Stock Concession
For small businesses, the ATO provides a significant simplification. Under section 328-285 of ITAA 1997, if the difference between the value of opening stock and a reasonable estimate of closing stock is $5,000 or less, the entity can treat the opening and closing stock values as equal — effectively ignoring the change in stock for tax purposes.
This means no stocktake is required, no calculation is needed, and the opening stock figure simply rolls forward to closing stock. The income tax impact of the stock movement (up or down) is zero.
The key conditions:
- The entity must be an SBE (aggregated turnover under $10M)
- The difference between opening stock and a reasonable estimate of closing stock must be $5,000 or less in absolute value
- "Reasonable estimate" means the business must have a genuine basis for the estimate — a quick visual assessment is fine, but outright guessing is not
For clients with low inventory levels — sole traders carrying a small range of products, service businesses that hold minimal stock of consumables — this concession eliminates the year-end stocktake entirely. It's a legitimate, practical simplification that many eligible clients don't know about.
However, the concession is not always advantageous. If closing stock has fallen significantly below opening stock (because items have been sold, consumed, or written off), recognising that decrease produces a deductible outcome that reduces taxable income. Using the concession in this scenario would forego that deduction. The bookkeeper should do a quick calculation before defaulting to the concession.
Year-End Stocktake Obligations
For businesses that cannot or do not use the small business concession, a physical stocktake at year-end (30 June) is required to determine the quantity and condition of closing stock. The ATO does not prescribe the format of a stocktake, but it expects records that can support the closing stock value if the return is reviewed.
Best practice for a year-end stocktake:
- Count and record each item category, not just total value
- Note the condition of stock — separate damaged, obsolete, or slow-moving items that may warrant market value or write-down treatment
- Retain the stocktake sheets as part of the tax records for at least five years
- Reconcile the physical count to the perpetual inventory records in the accounting system — differences should be investigated and adjusted before the closing stock figure is finalised
Practical Guidance: Matching the Method to the Client
For most retail clients with relatively stable product ranges and costs, average cost provides a consistent, defensible year-end figure without requiring individual item tracking. It works well with most inventory modules in accounting software.
For clients with discrete high-value items (machinery dealers, jewellers, equipment hire businesses), FIFO with individual item tracking is often more appropriate — the cost of each identifiable unit is tracked from purchase to sale.
For clients with slow-moving, obsolete, or seasonally perishable stock, market selling value for those specific items in combination with cost for the remainder can produce the most tax-efficient and commercially accurate result.
Document the valuation method election in the client file each year, even when it doesn't change. If the ATO ever queries the closing stock figure, having a clear record of which method was applied to which items — and why — is the best protection.