Q4 Profit Plan for Multichannel Sellers: Check This Before Black Friday

Q4 is where experienced sellers make a large share of the year's revenue, and also where a lot of it leaks away. Discounts, higher fulfilment costs, extra ad spend and returns all land at once, and revenue reports look great while profit quietly shrinks. This guide sets out what to check before Black Friday (Friday 27 November 2026) and Cyber Monday (30 November) so the peak makes money, not only sales.

Start with unit economics, not the sales target

UK commentary on Q4 planning keeps coming back to the same point: your strategy should start with unit economics. Before you set a revenue goal, work out what each SKU earns per unit after cost of goods, marketplace fees, fulfilment, shipping, advertising and an allowance for returns. Anything with a thin margin before Q4 will go negative once you discount it and add peak costs.

Five checks before the peak

• Margin per SKU on each channel. The same product earns different amounts on Amazon, eBay, B&Q and your own store. Decide which channel gets the stock.
• Peak costs. Amazon's festive peak fulfilment fee applies to eligible FBA units from 15 October 2026 to 14 January 2027, so any FBA product needs its margin re-checked for those months.
• Discount depth. Work out how much extra volume each promotion needs to break even before you agree to it. Our guide to Black Friday discount break-even shows the maths.
• Advertising targets. Competition for clicks rises, so your break-even ACoS for each product matters more than a single account target.
• Stock cover. Running out loses the sale and the ranking you built, while overbuying ties up cash into January.

Decide what you are optimising for

Revenue, profit and cash flow are three different goals, and Q4 forces a choice. A clearance push may be worth a lower margin to free up cash. A hero product may deserve more ad budget because it brings in customers who come back. Write the goal for each product down before the promotion starts, so you can judge the result honestly afterwards.

Watch it live, not after the event

The risk in Q4 is finding out in January. Fees, refunds and ad costs reach your reports with a delay, so a campaign that looked profitable during the week can show a loss once everything has settled. Live profit per order and SKU lets you pause or reprice a product while it is still happening. WhatSales shows this across the marketplaces you connect.

After the peak

Plan for January now. Refunds from December sales arrive after the revenue was booked, peak fees continue until 14 January, and any overstock needs a plan. Reviewing profit by SKU in the first weeks of the new year tells you what to repeat next November and what to drop.

When does Q4 selling start?

For sellers, it starts well before Black Friday. Fulfilment deadlines fall in early autumn, and Amazon's peak fee begins on 15 October.

What is the most common Q4 mistake?

Judging promotions on sales volume alone. A promotion that doubles units can still lose money once discount, fees, shipping and returns are counted.

Should I discount every product?

No. Discount the products whose margin can afford it, or where the goal is clearance or customer acquisition, and protect margin on the rest.