E-commerce finance: contribution margin

What good finance answers

An e-commerce review should answer:

• What is the contribution margin by product, order, campaign, marketplace, and channel?
• Does inventory cost include purchase price, inbound freight, and duties under the chosen policy? Are per-order packaging and fulfillment shown separately?
• Which marketplace, payment, and fulfillment fees changed from the previous period?
• What do returns and refunds cost after reverse shipping, processing fees, and inventory write-downs?
• Can available cash support purchase orders and inventory lead time before the related payout arrives?

Use the product and channel margin workflow to compare the costs behind each sale.

Pressure points

Data is split across orders, payouts, and books

Orders, payouts, fees, ad spend, and accounting entries often have different dates and identifiers. Reconcile order and settlement totals before comparing margins.

Landed cost changes between purchase cycles

Purchase price, freight, duty, and currency can change while the storefront price stays fixed. Apply the chosen inventory-cost method consistently; keep outbound packaging and fulfillment separate from the cost of acquiring stock.

Fees are deducted before cash arrives

Payouts may net sales against fees, refunds, reserves, and adjustments. Review settlement detail instead of recording the net deposit as sales.

Returns create delayed margin loss

The sale and refund may fall in different periods. Match the refund to its original order, then account for return shipping, fees, and the condition of any stock received back.

Operating rhythm

Cadence	Review	Decision output
Weekly	Payout exceptions, stock risk, returns, ad spend, expected supplier payments	Pricing, promotion, reorder, and cash actions
Monthly	Product and channel margin, landed cost, fee changes, inventory reconciliation	Assortment, channel, vendor, and cost corrections
Quarterly	Inventory method, supplier terms, return patterns, channel mix	Purchasing plan, policy review, and capital allocation

When purchasing decisions create a timing problem, use the cash timing and liquidity workflow with expected payouts and supplier commitments.

AI with controls

AI can compare orders, settlement lines, and costs only when those records are available. It cannot reconstruct missing order identifiers, inventory counts, or a costing policy.

A controlled e-commerce workflow should:

1. State the order, payout, return, and accounting periods included in the review.
2. Reconcile gross sales to discounts, refunds, fees, reserves, and cash received.
3. Link margin findings to SKU, order, channel, settlement, vendor, and cost records.
4. Flag missing landed-cost components, negative inventory, duplicate fees, and timing differences.
5. Keep inventory policy, tax treatment, pricing, purchasing, and write-off decisions with qualified people.

MosoFin’s live finance-data agent currently retrieves QuickBooks records in Claude. It does not provide a live Shopify orders, payout, inventory, or ad-spend connection. Check the current source and agent availability, and provide exports or other records before asking for SKU or channel margin.