Buying an E-Commerce Business: Due Diligence and What to Verify Before You Close

E-commerce businesses are some of the most commonly listed small businesses on the market, and some of the easiest to misread. The numbers sit right there in a Shopify or Amazon dashboard, which makes it feel like the diligence is already done. It isn't. A dashboard shows what the platform wants to show you, the way it wants to show it.

Why e-commerce deals are different

Most service businesses sell time. An online store sells products through platforms the seller does not control, funded by ad spend that does not transfer with the business, and stocked with inventory that can lose value quickly. That changes where the risk lives.

What to look at

Area	What to verify
Net revenue	Gross sales minus returns, refunds, discounts, and chargebacks. Revenue reported before returns can overstate the real number.
Channel mix	Revenue split by own website, Amazon, wholesale, and other marketplaces. Each channel has different fees and different risk.
Contribution margin	Profit after product cost, shipping, platform and payment fees, and advertising. This is the number that shows whether the business really works.
Advertising dependence	Ad spend as a share of revenue, the trend in return on ad spend, and how much revenue comes from organic search, email, and repeat customers.
Inventory	Quantity, age, condition, and landed cost, including freight and duties. Not all inventory is worth what the books say.
Repeat customers	Share of revenue from returning buyers. Repeat revenue is cheaper and steadier than revenue that has to be bought with ads every time.
Concentration	Revenue by product, by platform, and purchases by supplier.

1. Revenue: gross, net, and what actually got paid

Start with the platform's own reports (Shopify sales reports, Amazon settlement reports) and tie them to the bank. Platforms pay out net of fees, can hold back reserves, and pay on a delay, so a month of sales rarely matches that month's deposits. That is normal. What matters is whether it reconciles. It is the same idea as a proof of cash, and it is the first test we would run on any online store. We explain how it works in our guide to the proof of cash.

Also check when the seller records revenue. Many small sellers book it when the payout arrives, not when the order ships. That can shift income between months, or even years, right around a sale.

2. Profit after advertising

Gross margin makes e-commerce look better than it is. A store can show a healthy gross margin and still keep very little after paying for ads, platform fees, shipping, and returns. Build the P&L all the way down to contribution margin, by channel where the data allows it.

Then look at ad spend over 24 months. If ad costs have been climbing while revenue stays flat, today's profit may be borrowed from tomorrow. Ask how much traffic would survive if the owner stopped running the ads.

3. Inventory

Inventory is often the biggest asset and the biggest argument. Ask for a report by product with quantity, cost, and age. Look for slow movers, damaged or expired goods, inventory in transit, and stock sitting in marketplace warehouses, where aged units can carry extra storage fees. Check that the cost on the books includes freight and duties, because landed cost is the real cost.

In many online store deals, inventory is priced separately from the business and counted at closing. That is common, not universal, so settle how it will be counted and valued before you sign. Our guide to inventory and receivables in due diligence goes deeper on this.

4. Concentration risk

• One platform. If most sales run through a single marketplace, a suspended account can stop revenue overnight.
• One product. A couple of bestsellers carrying the whole business is a fragile setup, especially if competitors can copy them.
• One supplier. A single factory or distributor with no backup is a risk. Ask about contracts, pricing history, and minimum orders.

The same logic behind customer concentration risk applies here, except the concentration is in products, platforms, and suppliers instead of just customers.

5. Sales tax and other liabilities

Marketplaces like Amazon generally collect and remit sales tax on sales made through their platforms. Sales through the seller's own website are different. Depending on where the customers are and how much the store sells, the seller may owe sales tax in states where it never registered. Unpaid sales tax is a liability that can follow the business, so ask whether the seller has ever reviewed this and talk to a tax professional. Also look at unfulfilled orders, gift cards, store credit, and return obligations.

6. The owner's job and the add-backs

Most online store owners wear many hats: sourcing, ad management, customer service, and fulfillment. In a QoE, the owner's pay and personal expenses get added back. But you also need to subtract the cost of replacing the work the owner does. If the founder runs the ads and handles the supplier relationships, someone has to be paid to do that after you take over.

Also look at software subscriptions, contractors (including offshore help paid informally), and personal items run through the business. For more on how this works, see adjusted EBITDA and how it can be inflated and SDE vs. EBITDA.

7. Seasonality and the trailing twelve months

Many online stores earn a big share of the year in the fourth quarter. A trailing twelve month figure that ends right after the holidays looks great. One that ends in summer looks weak. Look at 24 to 36 months, month by month, to see the real shape.

Also watch for a store that was pushed hard just before the sale: heavy discounting to clear stock, or ad spend cut to boost short term profit.

8. What actually transfers

A deal can look clean on paper and still hit trouble at closing. Confirm exactly what you are getting: the domain, the store and platform accounts, social accounts, email lists, trademarks and brand registrations, supplier contracts, and software licenses. Some platforms restrict how seller accounts can change hands, so check each platform's rules, and have your attorney review the purchase agreement, before you assume everything comes with the business.

What a QoE checks in an e-commerce deal

• Revenue tied to platform reports, bank deposits, and tax returns
• Net revenue after returns, discounts, and fees
• Gross margin and contribution margin, by channel where the data supports it
• Add-backs and the cost of replacing the owner's work
• Inventory and working capital
• Month by month trends and seasonality

A QoE will not value the brand or forecast how your ads will perform. What it does is tell you whether the earnings are real and repeatable, so you are negotiating on numbers you can trust.

Common questions

Are online stores valued on SDE or EBITDA?

Smaller stores that depend on the owner are usually priced on seller's discretionary earnings (SDE). Larger ones with a management layer are more often priced on adjusted EBITDA. Our guide to SDE vs. EBITDA explains the difference.

Can I trust the numbers in the Shopify or Amazon dashboard?

Use them as a starting point, not as proof. Dashboards can show gross figures, leave out refunds that come later, or be filtered in ways that flatter the business. Tie them to bank deposits and tax returns.

Is inventory included in the purchase price?

It depends on the deal. In many online store acquisitions, inventory is priced separately and counted at closing. Agree on how it will be valued, and how damaged or aged stock is handled, in the letter of intent. See our LOI guide for what to include.

Is a QoE worth it for a small online store?

If you are putting real money or SBA financing behind the purchase, it is worth considering. E-commerce earnings are easy to misread, and the cost of a QoE is small next to the cost of overpaying for a store whose profit turns out to be thinner than the dashboard showed.