Same SKU, Two Channels: Growth or Cannibalization?

Most sellers reach a familiar fork: the product does well on Amazon, so they launch it on their own Shopify store too — or vice versa. More channels, more shelves, more sales. What could go wrong?

The trap is subtle. When total revenue goes up after you add a channel, it feels like growth. But there are two very different stories that produce the same top-line chart, and only one of them is actually making you money:

• Incremental demand: the new channel reaches buyers the old one never would have. Total sales genuinely grow.
• Cannibalization: the new channel mostly captures buyers who would have purchased on the old one anyway. The revenue just moved seats — and if the new channel has worse margins, you're now less profitable at the same or higher total volume.

Both look like an up-and-to-the-right revenue line. The difference is everything, and the blended number hides it.

Why "total sales went up" isn't the answer

Adding a channel almost always lifts total sales somewhat, because no two channels reach exactly the same audience. That small truth is what makes cannibalization so easy to miss — there's always enough real growth to justify the story you want to believe.

The question is never "did total sales go up." It's "did they go up more than they cost me." A sale that shifts from your 30%-margin DTC store to a lower-margin Amazon listing (after referral fees, FBA, and ad spend) can grow revenue while shrinking profit. A blended P&L will happily show a bigger top line and a thinner bottom line, and you won't know which channel to blame.

Revenue moving from a high-margin channel to a low-margin one is not growth. It's a discount you didn't mean to give.

The three outcomes of putting one SKU on two channels

When the same SKU lives on both Amazon and your DTC store, one of three things is happening. Naming them is the first step to measuring them.

• Halo (win–win): presence on one channel lifts the other. Amazon acts as a discovery engine and brand-search rises on your DTC site; or your DTC content and ads drive branded searches that convert on Amazon. Total demand grows and each channel benefits.
• Cannibalization (win–lose): the channels compete for the same buyer. Every unit the new channel gains is roughly a unit the other loses. Feels flat-to-positive on top line, often negative on margin.
• Independent (neutral): the channels reach genuinely different audiences and barely interact. Adding one doesn't move the other much in either direction.

The strategic move is different for each. Halo SKUs deserve more cross-channel investment. Cannibalizing SKUs need a deliberate decision — differentiate the offer, split the assortment, or concentrate on the higher-margin channel. Independent SKUs can be optimized channel-by-channel without worrying about spillover.

Signals that tell them apart

You can't see this in a single revenue chart, but the pattern shows up when you line the channels up side by side over time.

Two things make these signals trustworthy. First, look per SKU, not per channel — a brand-level view averages your halo products and your cannibalizing products into a meaningless middle. Second, account for timing and stockouts — a channel that only grows while the other is out of stock isn't finding new demand, it's absorbing displaced demand.

Comparing channels fairly

The comparison only works if both sides are measured on the same terms, and that's where it usually breaks. A $30 sale on your DTC store and a $30 sale on Amazon are not the same sale:

• DTC carries payment processing, shipping, and customer acquisition cost — but you keep the margin and the customer relationship (and the data, and the repeat purchase).
• Amazon carries referral fees, FBA/fulfillment, storage, and often ad spend to stay visible — but brings built-in traffic and trust.

Cannibalization only matters in the context of contribution margin per channel, not revenue. Moving a sale from a channel that nets you $12 to one that nets you $6 is a real loss even if the sticker price is identical. And DTC's higher lifetime value — repeat purchases you own rather than rent — means a "smaller" DTC channel can be worth defending even when Amazon looks bigger on volume.

A simple way to check

You don't need a data-science team. You need to stop looking at the blended number and start looking at the SKU across channels, over time.

1. Classify the SKU. Is this product sold on one channel or both? The same-SKU-on-both cases are the only ones where cannibalization is even possible — start there.
2. Line up the timelines. Put per-SKU units and revenue for each channel side by side, and mark the moments that matter: launches, promotions, stockouts, ad-spend changes.
3. Normalize to margin. Convert both channels to contribution margin per unit so you're comparing profit, not sticker price.
4. Read the pattern. Did adding the channel grow the total after margin, or did it move profit from a better channel to a worse one? Halo, cannibalization, or independent?
5. Act per SKU. Invest more in halo products, make a deliberate call on cannibalizing ones, optimize independent ones in isolation.

The bottom line

Selling the same SKU on Amazon and DTC isn't automatically good or bad — it depends entirely on whether the channels are helping each other, fighting each other, or ignoring each other. That answer is invisible in a blended revenue chart and obvious once you compare the channels per SKU, on a margin basis, over time.

That's exactly what Meridian Flows is built to do. Our SKU classification engine identifies which products you sell on one channel versus both, and the multi-channel analytics compare Amazon and DTC performance on the same terms — so you can see whether a shared SKU is riding a halo effect or quietly cannibalizing your best margins before you pour more budget into it.

Want to know which of your SKUs are helping each other and which are competing? Start a free trial and run your catalog through a channel-by-channel breakdown.