Amazon seller CFO services: know your true margin before you scale it

What a fractional CFO changes for an FBA business

Bookkeeping tells you what happened; CFO work decides what happens next. For Canadian Amazon sellers that comes down to four recurring decisions: what each unit really earns, when to reorder and how much, how to fund the inventory, and what the business must look like on paper to sell one day. We run this as a monthly cadence on top of clean accrual books — margin review by SKU, rolling cash forecast, purchase-order plan — with fixed fees quoted after a discovery call.

Sellers usually reach for this help when a second or third SKU starts competing for the same cash, or when a Seller Central dashboard says the account is profitable while the bank balance says otherwise. Both are unit-economics problems wearing different costumes.

True unit economics: the margin after Amazon is paid

The only margin worth scaling is what remains after referral fees, FBA fulfillment, storage, advertising, and returns — not the spread between landed cost and list price. Amazon's referral fee runs 15% in most categories, and ad spend behaves like a variable cost of sale, so we allocate it per unit instead of leaving it as a lump at the bottom of the income statement. Here is an illustrative waterfall for a $40 USD product — your fees will differ by size tier, category, and ad strategy:

Run this waterfall for every SKU and the rankings change: the hero product by revenue is often third by contribution once its ad dependence is priced in. That reordering decides where the next purchase-order dollar goes — and which listings should be repriced, bundled, or retired.

Inventory cadence: the decision that eats your cash

Reorder size and timing set your cash conversion cycle, and for most FBA sellers that cycle is brutal: deposit to the supplier, weeks of production, ocean freight, check-in at the fulfillment centre, then a sales curve — while Amazon settles with you every two weeks. Funding a 90-day pipeline out of a 14-day payout loop is why profitable sellers feel broke.

We rebuild that cycle SKU by SKU — supplier terms, production and transit days, Amazon's rolling reserve, and the velocity the listing can actually sustain — then lay every planned purchase order over the forecast. The output is specific: the weeks the account goes cash-negative, shown before the deposit is wired rather than discovered after. Three levers move the curve more than any other:

• Stagger purchase orders so no two SKUs demand deposits in the same month.
• Split air and sea freight when a stockout would cost more in rank than the air premium costs in margin.
• Model Q4 explicitly — the inventory build for November is paid for in August, and that gap belongs in your forecast, not your overdraft.

Funding growth: Amazon lending against the bank

Financing offers inside Seller Central are fast and underwritten on your sales data, but they are priced for convenience and repaid straight out of your payouts, which tightens the very cash cycle you are trying to loosen. Canadian banks and BDC are cheaper but slower, and many struggle with an inventory-heavy business that has no receivables. The tiebreaker is arithmetic, not loyalty: compare the all-in cost of each dollar against the contribution margin the borrowed inventory will actually earn, using the per-unit numbers above. Borrowing in CAD to buy USD inventory also adds a currency mismatch worth pricing in before you sign. Timing matters as much as source: the cheapest financing is arranged from a position of strength, months before the Q4 build, not in October when every lender can see you need it.

Exit readiness: aggregators still buy clean books

FBA businesses trade on a multiple of seller's discretionary earnings, and every buyer — aggregator, brokerage listing, or private buyer — discounts what they cannot verify. Exit-ready means accrual books with COGS matched to units sold, documented add-backs, ad spend tied to SKUs, and USD revenue converted consistently, ideally maintained for two full years before you list. It also means a clean cross-border position: a Canadian seller on amazon.com should have their US filing posture settled long before due diligence, which is covered in depth on our cross-border accounting page for Amazon sellers. If the books need rebuilding first, our bookkeeping team handles that before the CFO work starts — advice layered on bad data is just confident guessing.