CB2101 Chap.6 Variable Costing and Segment Reporting
Variable Costing and Segment Reporting
Separate timing from accountability
Variable and absorption costing differ in when fixed manufacturing overhead becomes expense as inventory changes. Segment reporting uses contribution margin and traceable fixed expenses to show segment margin.
Allocated common costs remain outside the segment's contribution because closing one segment does not necessarily remove them.
Locate fixed manufacturing overhead
Variable costing treats fixed manufacturing overhead as a period expense, while absorption costing attaches it to units produced. Neither method says the resource is imaginary; they differ in expense timing.
When production exceeds sales, absorption costing defers part of fixed overhead in ending inventory. When inventory falls, previously deferred overhead reaches expense.
Reconcile profit through inventory
Multiply the inventory-unit change by fixed manufacturing overhead per unit and attach the direction.
An inventory increase makes absorption profit higher because cost is deferred; a decrease makes absorption profit lower because old cost is released. Across the full life of the inventory, cumulative profit converges when every unit is sold, assuming consistent classifications.
Build a segment contribution statement
Sales less variable expenses produces contribution margin.
Subtract traceable fixed expenses to find segment margin, the amount the segment contributes toward common fixed cost and company profit. This layout preserves the distinction between costs the segment causes and allocations made for reporting convenience.
Put common fixed expenses below the combined segment margins.
Test traceability over the decision horizon
A cost is traceable when the segment causes the resource commitment and closing the segment removes it after the relevant delay. A lease may continue this month but disappear at renewal; a shared executive salary may remain entirely.
State the horizon and the cash-flow effect rather than treating fixed as synonymous with unavoidable.
Evaluate closure with avoidability
Dropping a segment loses its contribution margin and saves only the fixed costs that disappear. Common allocations that continue are excluded. Add companion-sales effects or contribution from an alternative capacity use only when the facts support them.
Finish with the company-wide change, not the segment's allocated bottom line, and name the assumption most likely to reverse the result.
What this chapter covers
- 01
Variable and absorption product cost
- 02
Inventory change profit bridge
- 03
Contribution-format statements
- 04
Traceable fixed expenses
- 05
Common fixed expenses
- 06
Keep-or-drop decisions
Worked example · free
Read past an allocated segment loss
- 2Compute segment margin.
- 2Identify continuing common cost.
- 2State the closure effect.
Key terms
- Variable Costing
- An internal product-costing approach that expenses fixed manufacturing overhead in the period.
- Segment Margin
- Contribution margin remaining after the segment's traceable fixed expenses.
- Common Fixed Cost
- A fixed resource supporting several segments that does not disappear with one segment.
Variable Costing and Segment Reporting FAQ
Why do variable and absorption profits differ?
When inventory changes, absorption costing defers or releases fixed manufacturing overhead through inventory. Variable costing expenses the period's fixed manufacturing overhead immediately, so the timing difference follows the inventory movement.
What makes a fixed cost traceable to a segment?
The segment must cause the resource commitment and removing the segment must eliminate the cost after any relevant delay. An allocation based on revenue or another convenient base does not establish traceability.
Should a segment with a reported loss be dropped?
Not automatically. Compare contribution margin lost with fixed costs genuinely avoided and any benefit from released capacity. Continuing common allocations do not become savings when the segment closes.
How do I reconcile absorption and variable profit?
Multiply the change in inventory units by fixed manufacturing overhead per unit and attach the direction. Inventory growth defers cost under absorption, making absorption profit higher; inventory decline releases deferred cost, making it lower. Check that the difference reverses when the inventory is sold, because the methods change timing rather than cumulative profit over the full inventory life.
Exam move
Practise reconciling variable and absorption profit from the inventory-unit change and fixed manufacturing overhead rate. Write the direction before multiplying: an inventory increase makes absorption profit higher, while a decrease releases deferred cost. Build one contribution-format segment statement from sales through variable expenses, contribution margin, traceable fixed expenses and segment margin.
Highlight traceable, common and avoidable as three separate labels before computing a closure effect. Test each fixed cost over the stated time horizon and identify allocations that continue. Add companion-sales or alternative-capacity effects only when the facts support them. Finish by comparing the reported segment bottom line with the company-wide profit change and explain why the two can point in opposite directions.
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