The most common method for evaluating product performance in ecommerce is the gross margin percentage. A SKU with a gross margin of approximately seventy percent is assumed to be a strong performer that deserves commercial focus and inventory investment. The operational team prioritizes keeping this item in stock, and the marketing team directs acquisition spend toward it.

The illusion is that gross margin only accounts for the physical cost of the product. It ignores the variable expenses required to process the payment, pick and pack the order, ship it to the customer, and manage the return. When these variable costs are applied at the unit level, the profitability of the SKU changes. A product with a high gross margin but a high return rate or complex fulfillment requirements can generate a negative contribution margin on every transaction. City Shift Finance has analyzed how the contribution margin below the gross margin line reveals products that are actively destroying cash. This misreading is also a primary reason why ROAS optimization drives spend toward the wrong SKUs.

Continuing to invest capital in high-revenue, negative-contribution SKUs is a common path to financial distress. The business scales its revenue and expands its warehouse footprint, while its operating cash flow deteriorates. The root cause is not a sales problem; it is a portfolio reporting problem that misidentifies unprofitable products as core drivers of value.

Resolving this requires shifting the basis of portfolio evaluation from gross margin to unit-level contribution margin. This was a critical step in the Bime Beauty revenue management intervention, where the commercial team recalculated product profitability to include channel-specific fulfillment and return costs.

The catalog sheet shows a seventy percent margin. The unit contribution statement shows a cash drain.