What it means
When you run a business, the items you buy to sell to customers are recorded on your balance sheet as inventory, normally at their original purchase price. However, markets change, and goods can lose value because of new technology, shifting consumer tastes, or cheaper alternatives.
The Lower of Cost or Market rule protects you and your stakeholders from thinking your inventory is worth more than it actually is. Think of it as a reality check for your balance sheet.
If you bought winter coats for $50 each, but a warm winter means nobody is buying and you can now replace them for $30, keeping them on your books at $50 is misleading. The rules force you to write the coats down to $30, which stops you reporting profits on goods that have lost their appeal and value.
This conservative approach recognises likely losses straight away but does not recognise gains until the goods are sold. In practice, this rule applies mostly to retailers, manufacturers, and wholesalers.
At the end of every accounting period, usually quarterly or annually, finance teams review inventory values. If the market value has dropped below cost, they take an immediate hit to net income by recording a loss, which also sets up more realistic profit margins for when those items eventually sell.
While it sounds simple, applying the rule requires regular market research. You must look at current replacement costs, expected selling prices, and the cost to complete and sell the goods.
Many modern frameworks now use net realisable value, the expected selling price less the costs to complete and sell, in place of replacement cost. It keeps financial reporting honest, ensuring that anyone reading your financial statements sees a realistic picture of your assets without inflated expectations.
Imagine buying a used car for $5,000 to resell, and six months later the market crashes and similar cars sell for $3,000. You must value the car at $3,000, because that is what it is truly worth today.
In practice
Real-world examples
Example 1
A boutique clothing shop bought 100 summer dresses for $30 each. Due to a sudden style shift, similar dresses now wholesale for $20 each. The shop must value the dresses at $20 on its balance sheet, which creates a write-down of 100 x $10 = $1,000.
Example 2
An office furniture supplier holds 40 ergonomic desks purchased at $150 each. A competitor introduces a superior model, causing the market value to drop to $120. The supplier adjusts inventory value downward by 40 x $30 = $1,200 to reflect the new market reality.
Example 3
A hardware store stocks 600 specialised lightbulbs bought at $5 each. Because local building codes change, demand plunges, and suppliers drop replacement prices to $2. The store writes down the inventory by 600 x $3 = $1,800 and reports the loss in the period when the price fell.
Think of it
Imagine buying a used car for five thousand pounds to resell. Six months later, the market crashes and similar cars sell for three thousand pounds. You must insure and value the car at three thousand pounds, because that is what it is truly worth today.
Formula
Calculation
Inventory Value = MIN(Historical Cost, Market Value)
Worked example: the historical cost of a laptop is $400 and the current market replacement cost is $350. MIN($400, $350) = $350, so the laptop is recorded on the balance sheet at $350. For 100 laptops the cost is $40,000, the market value is $35,000, and the write-down is $40,000 - $35,000 = $5,000.
Under the traditional version of the rule, "market" is the replacement cost, but it is limited by two boundaries. The ceiling is net realisable value (NRV) and the floor is NRV less a normal profit margin. Suppose a laptop can be sold for $420 with $30 of selling costs and a normal profit of $60. NRV = $420 - $30 = $390 and the floor = $390 - $60 = $330. The $350 replacement cost sits between $330 and $390, so market value is $350 and the laptop is carried at the lower of $400 and $350, which is $350.Case study
Seen in the real world
This is a fictional, illustrative scenario. BrightTech, a mid-sized consumer electronics retailer, stocked up on portable DVD players, purchasing 500 units at $40 each. Over the next year, streaming services surged in popularity, rendering portable DVD players largely obsolete. Wholesale replacement costs plummeted to $15 per unit.
At the end of the financial year, BrightTech's finance manager applied the Lower of Cost or Market rule. Instead of keeping the inventory valued at the original $20,000, the team calculated the new market value at $7,500 (500 units multiplied by the new $15 replacement cost). BrightTech recorded a write-down of $12,500 as an expense on the income statement. This adjustment reduced that year's net income, saving the company from reporting phantom profits.
The effect carried into the next year. When BrightTech later sold the remaining players at about $15 each, it reported no further loss, because the stock was already carried at that value. Without the write-down, the same sale would have shown a $12,500 loss in the following year and mixed an old purchasing mistake into that year's results. Bank lenders reviewing the accounts saw a clean and honest balance sheet.
Watch out
Common mistakes
- Confusing market value with the final retail selling price.
- Failing to review inventory values regularly as market conditions change.
- Applying the rule to individual items instead of categories when permitted.
Questions
People also ask
What does market mean in this context?
Market generally means the current replacement cost, bounded by the net realisable value, which is the estimated selling price minus disposal costs.
Can I write my inventory value back up if the market recovers?
Under standard international accounting rules, reversals are sometimes allowed, but under US GAAP, once inventory is written down, it cannot be written back up.
Why is this rule considered conservative?
It anticipates potential losses immediately by reducing asset values, but does not anticipate potential gains until the inventory is actually sold.