Why You Should Use Sell-Through Data to Plan Smarter Buys

If you are staring at a blank spreadsheet trying to forecast your Spring/Summer 2026 line, you probably feel that familiar mix of excitement and anxiety. 

Planning an assortment used to be equal parts art and gut feeling. You would look at what shipped last year, add a trend multiplier, and hope for the best.

But as we head into 2026, hope isn’t a strategy. The cost of carrying inventory is too high, and retailers are too selective to accept a scattershot approach.

To make sure you secure shelf space in 2026, you’ll have to flip the script. Instead of relying on sell-in data (what you shipped to the retailer), build your strategy around sell-through data (what the consumer actually bought). 

Here’s how you can use that data to build a smarter, tighter, and more profitable assortment for the year ahead.

The Trap of Sell-In Planning

For decades, wholesale brands measured success by how much product they got out the door. 

If you shipped 10,000 units of a new neon windbreaker, it looked like a win on the P&L. But if 4,000 of those windbreakers are still sitting on a rack in Des Moines come August, it’s actually much less of a win and much more a liability. 

Focusing solely on sell-in data creates a false positive feedback loop. You might repeat a style because you shipped a lot of it, unaware that it clogged up your retailers' open-to-buy dollars and damaged your margin with end-of-season markdowns.

Why 2026 Demands a Data-First Approach

The retail landscape has shifted. According to industry analysis, retailers are increasingly using AI and advanced analytics to optimize their own buys. They are moving away from massive upfront commitments and toward chase strategies where they buy narrower assortments and reorder what works.

If your retailers are using data to buy, you need to use data to sell.

Using a platform like RepSpark allows you to close the loop. By analyzing reorder velocity and digital catalog engagement, you can see not just what retailers bought, but what they needed more of. 

This visibility allows you to align your 2026 production with actual consumption, not just optimistic sales targets.

Step 1: Ruthlessly Segment Your SKU List

The first step in your 2026 planning is to ruthlessly segment your SKU list. Look at your sell-through reports. You will likely see that a small percentage of your styles drive the vast majority of your volume and margin.

These are your never-outs. For 2026, your strategy for these items should be operational excellence. Don't change the fit. Don't mess with the fabric. Your goal here is to ensure you have the raw materials booked to support 100% in-stock rates.

At the same time, look for the churners: styles that had high initial sell-in but zero reorders. This indicates that while the concept was attractive to buyers, the product didn't resonate with the end consumer. These are the styles you cut from the line to free up cash for innovation.

Step 2: Analyze Regional Nuances

Data can stop you from making broad, sweeping generalizations. A heavy knit sweater might have a poor national sell-through rate, making it look like a loser. But when you drill down into your data, you might see it had an 85% sell-through in the Northeast and Pacific Northwest.

In 2026, a smart assortment is a segmented one. Instead of killing that sweater, you can tag it as a Regional Key Item in your digital catalogs. This ensures that reps in the right territories push it, while reps in Florida know to skip it. This targeted approach increases your overall efficiency and prevents returns.

Step 3: Use Digital Engagement as a Focus Group

You don't have to wait for sales numbers to know if a product is a winner. Your B2B platform is essentially a 24/7 focus group. Look at the engagement metrics on your digital line sheets and community pages.

Which styles are being clicked on the most? Which images are being downloaded for social media? Which products are being added to carts but then abandoned?

If a particular colorway in your 2026 preview is getting 3x the views of the others, that is a strong signal to increase your buy depth on that SKU. Use this pre-season digital body language to adjust your production ratios before you cut the first purchase order.

Building a 2026 assortment strategy is less of a guessing game and more about listening to the signal your business is already sending you.

By pivoting from sell-in volume to sell-through velocity, you build a line that is easier for your reps to sell and easier for your retailers to turn. That is how you turn a spreadsheet of guesses into a roadmap for profit.

See how RepSpark can help you analyze your wholesale data to make data-driven decisions by scheduling some time with our team.