What Moved Gross Margin This Week?

The ending margin does not identify its cause

A lower margin can reflect a different product mix, deeper reductions, higher costs or several effects together. A single percentage cannot show which decision changed. It can also encourage teams to blame markdowns when the main driver sits elsewhere.

Atlas supports merchandise sales, cost and profitability analysis. The bridge here is an independent worked decomposition, not a claim of a preconfigured automatic explanation screen. Confirm the measures, periods and cost basis before relying on any saved report or calculated field.

Start from a comparable base

The base week sells a hundred units each of products A and B. A sells at $80 with $40 cost, contributing $4,000 GP. B sells at $100 with $50 cost, contributing $5,000. Total sales are $18,000 and product GP $9,000, a 50% margin.

The current week still sells 200 units overall, but its mix becomes 120 A and eighty B. Prices become $75 and $95; costs become $42 and $49. All figures are assumptions for the same two-product scope and exclude other operating expenses.

Measure the mix effect before the later changes

Apply current quantities to base prices and costs first. A contributes 120 times $40, or $4,800; B contributes eighty times $50, or $4,000. The subtotal is $8,800, a $200 reduction from the base despite unchanged total unit volume.

That isolates mix under this chosen order. It does not say volume or mix is always the most important driver. Another mathematically valid sequence can assign interaction effects differently, so label the method before comparing the bridge with another report.

Count realised price and reductions once

Next apply the current prices at current quantities and base costs. Each product’s price is five dollars lower, so the combined price effect is a $1,000 reduction: 200 units times $5. GP becomes $7,800 before the cost change.

If transaction evidence classifies $400 of that reduction as promotion and $600 as clearance, those reasons explain the same $1,000. They are not another reduction to subtract afterwards. A price bridge and a markdown-purpose analysis can coexist only if their overlap is reconciled.

A markdown classification must refer to the same sold units and baseline price as the bridge. Counting a permanent reduction and a later promotional offer as two full differences from original ticket can exaggerate the total. Reconcile the final realised price once, then retain the separate commercial reasons.

Read the cost effect on the same current quantities

A’s $2 cost increase across 120 units reduces GP by $240. B’s one-dollar cost decrease across eighty units improves it by $80. The net cost effect is a $160 reduction in gross profit, taking $7,800 to $7,640.

Current sales are $16,600 and goods cost $8,960, independently reconciling to $7,640 GP and approximately 46.0% margin. The calculation uses product goods cost on the stated basis, not a claim that every later invoice or overhead is already included.

Use the bridge to select a question, not assign blame

The $1,360 overall GP reduction consists of $200 mix, $1,000 price and $160 net cost in this sequence. The price component is largest, but its business reason still needs evidence. Planned promotion, exit activity and unexpected discounting require different responses.

Atlas supplies the analytical scope for the investigation. The bridge does not change a selling price, supplier quote or stock commitment. If the next action concerns those records, give it its own accepted evidence and authority rather than treating the chart as an operational instruction.

A cost movement can reflect a changed supplier quote, receipt mix or valuation basis. Confirm which is present before treating the $160 example as a negotiation opportunity. The bridge uses accepted example unit costs; it does not establish how an actual inventory ledger or later charge should be accounted for.

Finish with a reconciliation and an owned explanation

For this example, $9,000 less $200, $1,000 and $160 equals $7,640. Total units did not change, and price reductions were counted once. Retain the base, current values and order of calculation so another reviewer can reproduce the result.

Merchmix Atlas helps connect a margin movement with the product evidence behind it. A useful explanation narrows the next commercial question and makes its owner clear. It should describe the result faithfully, not manufacture a cause from whichever percentage looks most dramatic.

Keep favourable offsets visible as well as reductions. B’s eighty-dollar cost improvement does not erase A’s $240 increase; their net is $160. Showing both can lead to a different supplier or product question than a single blended cost figure that conceals the underlying changes.

Common questions