Financial due diligence for eCommerce is the process of verifying that an Amazon or Shopify business’s revenue, costs, and earnings are real, accurate, and reconciled to source data. It matters whether you’re selling or buying, because both sides are trying to answer the same question: does this business actually make what the seller says it makes?
In this guide, you’ll discover what buyers and their advisors dig into before wiring funds, how Amazon-specific line items like FBA fees and ASIN concentration factor into the review, and what a seller needs ready in the data room to avoid a painful price cut mid-negotiation.
You’ll walk away knowing exactly which numbers get tested first and how to make sure yours hold up.
What Must Be Proven Before an eCommerce Deal Can Close
Every dollar in your P&L has to trace back to a bank deposit, a settlement report, or an invoice, or it doesn’t count. Buyers aren’t just reading your numbers; they’re rebuilding them from raw data to see if the story matches.
That reconciliation habit underpins the entire review. A due diligence process for eCommerce acquisitions is often built around seven workstreams, and Quality of Earnings analysis alone can account for roughly 30% of the total effort in a middle-market deal. That weighting shows where buyers focus first.
The Records Sellers Need in the Data Room
A seller who shows up with three years of clean, exportable records moves through diligence faster and with fewer price adjustments. The data room should include:
- Profit and loss statements and balance sheets for the trailing 24 to 36 months
- Amazon Seller Central settlement reports and A2X reconciliation exports
- Shopify, Walmart, or TikTok Shop sales data if the business sells on multiple channels
- Supplier invoices and landed cost documentation for every active SKU
- Payroll records from Gusto or a similar system, plus any contractor 1099s
- State sales tax filings and nexus registration confirmations
How Buyers Should Set the Scope and Materiality Thresholds
Buyers should decide upfront what dollar threshold triggers a deeper look, rather than treating every transaction equally. A $50,000 discrepancy in advertising spend deserves more scrutiny than a $200 shipping supply variance.
Why Marketplace Businesses Need a Different Review
Amazon and Shopify businesses carry fee structures, inventory locations, and account health metrics that a generic small-business checklist never touches. The next section breaks down exactly how revenue and fees get tested against platform data.
Validate Revenue, Fees, and True Earnings
Gross sales on an Amazon dashboard almost never match what actually lands in the bank account, and that gap is where diligence starts. Buyers rebuild revenue from settlement data, not the seller’s summary numbers.
Reconcile Amazon Settlements, Shopify Sales, and Bank Deposits
A2X pulls Amazon and Shopify settlement data directly into QuickBooks Online, splitting each payout into sales, fees, refunds, and taxes. Without that mapping, a seller’s books often just show the net deposit as “Amazon income,” burying real fee costs.
A buyer will pull twelve months of settlement reports and match every deposit line by line. If the seller’s reported revenue doesn’t match the settlement totals within a small margin, that’s a flag worth investigating before moving forward.
Separate FBA Fees, Refunds, Chargebacks, and Promotional Costs
Lumping every Amazon charge into one expense line hides which cost categories are actually shrinking margin. A proper breakdown separates:
- Referral fees, typically a percentage of item price by category
- FBA fulfillment fees, based on size tier and weight
- Storage fees, split between monthly and long-term aged inventory
- Refund administration fees on returned units
- Chargebacks and A-to-Z Guarantee claims
- Coupon, deal, and Prime Day promotional discounts
A seller with $3 million in gross sales but $480,000 in unseparated “Amazon fees” has no way to judge which fee category is trending worse.
Test Advertising Cost of Sale and Contribution Margin Trends
Advertising cost of sale, or ACoS, shows how much of each sale went to Amazon PPC, and a rising trend over 12 months often signals eroding organic rank. A buyer comparing ACoS against contribution margin by SKU can spot products that only look profitable because ad spend is masking a pricing problem.
Scrutinize Seller Discretionary Earnings and EBITDA Add-Backs
Seller discretionary earnings, or SDE, is the profit left after operating costs plus reasonable owner compensation adjustments. Buyers push back hard on add-backs that feel inflated, like a $60,000 “one-time” consulting fee that recurs every year.
Clean, well-documented add-backs protect the multiple a business commands at close. The next question is whether the inventory sitting behind those earnings numbers is valued the way it should be.
Measure Inventory and Working Capital Without Distortion
Inventory is often the single largest asset on an eCommerce balance sheet, and it’s also the easiest place for numbers to drift from reality. A miscounted or mispriced inventory balance can quietly overstate profit for months before anyone notices.
Choose and Apply FIFO or Weighted Average Cost Consistently
FIFO assumes the oldest inventory units sell first, while weighted average cost blends the cost of all units together for each sale. Either method works for an Amazon seller, but switching between them mid-year without disclosure distorts cost of goods sold and confuses a buyer’s comparison across periods.
Verify Inventory Across FBA, 3PL, and Supplier Locations
A seller running inventory through Amazon fulfillment centers, a third-party warehouse, and an overseas supplier needs a reconciled count across all three. Buyers compare the seller’s stated inventory value against Seller Central inventory reports, and any unexplained gap raises questions about accuracy.
Inventory carries two roles in diligence: it’s both a working capital item and a quality-of-earnings item, since overstated stock inflates the balance sheet while understating true cost. That dual role is why buyers rarely accept a seller’s inventory count without independent verification.
Calculate Landed Cost, Aged Stock, Returns, and Write-Downs
Landed cost includes the unit purchase price plus freight, duties, and inbound handling fees, and it should be the basis for every COGS calculation. A buyer will ask for aging reports on slow-moving SKUs and expect write-downs already reflected for anything sitting unsold for 12 months or more.
Set a Realistic Working-Capital Target for Closing
Buyers and sellers negotiate a working capital peg, the minimum inventory and cash balance the seller must leave behind at closing. Setting that target too low starves the buyer’s first 90 days of operations, while setting it too high unfairly strips value from the seller.
Inventory numbers tell only part of the story once liabilities outside the P&L start surfacing.
Find Liabilities and Valuation Risks Outside the P&L
Some of the biggest deal-killers never show up on a profit and loss statement. They live in state tax filings, account health dashboards, and supplier contracts that a seller might not think to mention.
Quantify Sales Tax Nexus and Unpaid Filing Exposure
Sales tax nexus is the legal trigger requiring a business to collect and remit tax in a given state, often based on revenue or transaction volume there. A seller with unregistered nexus in eight states faces real liability that a buyer may discount from the purchase price or require the seller to resolve before closing.
Assess Account Health, Review Velocity, and Policy Risk
Amazon account health metrics, like order defect rate and policy violation history, directly affect how safe the revenue stream is going forward. Buyers will also check review velocity trends, since a sudden drop in new reviews per month can signal listing suppression or a quality issue the seller hasn’t disclosed.
Identify ASIN, Customer, Supplier, and Channel Concentration
Concentration risk means too much revenue riding on too few sources, and it’s one of the fastest ways to compress a deal multiple. Common concentration flags include:
- A single ASIN generating more than 40% of total revenue
- One supplier controlling the majority of unit production with no backup
- A single wholesale customer accounting for a large share of B2B sales
- Amazon representing 100% of revenue with no diversified channel
Review Contracts, Intellectual Property, and Platform Dependencies
Trademark registrations, supplier agreements, and any exclusivity clauses need to transfer cleanly at close. A buyer will also confirm the Amazon Brand Registry account and any patents are assignable, since a lapse there can delay or derail the transaction entirely.
With revenue, inventory, and liabilities tested, the last step is turning all of that verified data into a price both sides can defend.
Turn Clean Books Into a Defensible Deal Price
A business with reconciled, well-documented financials moves through diligence faster and closes at a stronger multiple than one with messy records. Buyers discount valuations for unclear financials because verifying accuracy takes time and carries risk.
Businesses with at least two to three years of organized, reconciled financial statements consistently earn stronger offers than those with inconsistent records. For a seven-figure Amazon seller, that difference often shows up as a fraction of a turn on the EBITDA multiple, which can mean hundreds of thousands of dollars on a mid-size deal.
Cleanup itself carries a cost worth planning for. Preparing books ahead of a sale can run $15,000 to $40,000 in professional fees over six months, but that investment can increase the purchase price by 5% to 15% and shave 30 to 60 days off the closing timeline.
Sellers who want to walk into diligence with numbers a buyer’s team can verify in days, not weeks, benefit from a CPA who works exclusively with eCommerce accounts. If you are weighing a sale within the next few years, schedule a free strategy call with AMZ Accountant to review your business’s valuation readiness and see exactly where your current books would slow a deal down.
Frequently Asked Questions
What is included in financial due diligence for an eCommerce business?
It includes verifying revenue against platform settlement data, testing inventory valuation, reviewing sales tax nexus exposure, and confirming seller discretionary earnings add-backs are accurate. Buyers also review account health, supplier contracts, and channel concentration before finalizing a price.
How far back should an Amazon or Shopify buyer review financial records?
Most buyers request 24 to 36 months of profit and loss statements, balance sheets, and settlement reports. A longer window shows whether revenue and margin trends are stable or seasonal spikes tied to one-time events.
What are the biggest financial red flags in an eCommerce acquisition?
Unreconciled revenue between settlement reports and the P&L, unexplained inventory value changes, and unregistered sales tax nexus in multiple states top the list. A heavy concentration in one ASIN, supplier, or customer also raises concerns quickly.
How do Amazon FBA fees and refunds affect seller discretionary earnings?
FBA fees, refund administration charges, and chargebacks directly reduce net earnings, so lumping them into one vague expense line can overstate profitability. Separating each fee category lets a buyer see which costs are rising and by how much.
Why does inventory valuation matter so much in an eCommerce deal?
Inventory is often the largest asset on the balance sheet, and using an inconsistent costing method between FIFO and weighted average can distort both COGS and reported profit. Aged or obsolete stock that hasn’t been written down also overstates the business’s true value.
Can unpaid sales tax reduce the purchase price of an online business?
Yes, unregistered nexus and unfiled sales tax liability are real financial exposures that a buyer factors into the offer. Sellers who resolve nexus registration and back filings before going to market avoid last-minute price reductions tied to this risk.