Why Peak trading problems rarely start at Peak
And how a proper Post-Mortem can improve your 2026 results
You've just come through peak. Sales were okay. Not terrible, but maybe not quite what you'd hoped for either.
The team worked incredibly hard. You made decisions quickly. You dealt with whatever came up. And now it's January, everyone's exhausted, and you're already thinking about next season.
But here's what I see happen time and again: brands skip the most valuable part. The bit where you actually sit down and figure out why things played out the way they did.
Because here's the truth - when peak doesn't deliver properly, it's rarely because of what happened during those intense trading weeks. Peak doesn't create problems, it just shines a light on decisions that were made months earlier. Your range. Your size curves. Your delivery schedule. Your cash allocation. Peak just tested whether those earlier calls were right.
A proper post-mortem connects the dots between what happened in November and December, and the decisions you made back in spring and summer. And if you do it now, while the memory is fresh, you can actually use those insights for 2026.
Peak just tests decisions you've already made
By November, the big calls are done. You've committed to a range. You've ordered quantities. You've set your size curves and agreed delivery dates. Pricing is locked. Cash is spoken for.
All peak does is put pressure on those earlier decisions.
The frustrating bit? A lot of brands hit the same problems every single peak. Not because the team keeps making mistakes during trading, but because the actual issues live much earlier in the process. In how the range was planned. In product development timelines. In critical path assumptions. In cashflow decisions made six months ago.
Peak doesn't create these problems. It just reveals them.
The Post-Mortem nobody wanted (but everyone needed)
In my corporate retail days, post-mortems were just part of the calendar. They happened twice a year, at the end of every season, and honestly? Nobody was ever excited about them.
Sometimes they were called "Stars and Dogs" sessions, which is more cute but tends to narrow everything down to just product performance. And while product matters, it's only part of what actually determines your peak results.
But here's the thing: those post-mortems were incredibly valuable because they forced you to understand why things happened the way they did, not just what happened. And that understanding is what let you make better decisions next time.
A lot of growing brands skip this step entirely. Peak ends, everyone's knackered, there's a collective sigh of relief, and attention immediately shifts to the next season. I get it. But that's exactly where opportunity gets lost.
The problem with just looking at Stars and Dogs
After peak, there's a natural instinct to simplify things. Pull up the sales report, see what sold out and what didn't, decide what to buy more of and what to avoid. It feels efficient.
Except it's not that simple, is it?
Because a product that sold well might have succeeded despite problems, not because everything went right. Maybe it would have done even better with proper size availability. Maybe you left money on the table because you couldn't repeat it.
And a product that underperformed? That might have been genuinely wrong for your customer, or it might have been let down by late delivery, poor presentation, or being buried in an overcrowded category.
When you only look at the end result, you miss the story behind it. And that's why the same issues tend to repeat themselves. Different products, same underlying problems.
A useful post-mortem connects product performance back to all the decisions that shaped it: planning, range structure, supply chain, pricing, marketing, cash allocation. That's where you find what actually needs to change.
The bits that actually matter
A useful post-mortem isn't just about pulling reports and ticking boxes. It's about connecting what happened during peak back to the decisions you made (and the constraints you were working within) much earlier in the year.
Here are the areas I go through with every brand I work with after peak:
1. Product and Range Structure
Start with product, absolutely. But go deeper than just "what sold" and "what didn't."
Did you have the right balance between choice and depth? Did you back your hero lines with enough stock and the right size curves? Or did you spread yourself too thin, with a bit of budget in lots of different areas but not enough weight behind the things that really mattered?
And here's a question worth asking: was too much money sitting in weaker categories that were never going to drive your results?
Having great individual products is one thing. Having a commercially strong, balanced range is something else entirely.
2. Size Availability
This one drives me mad because it's such a quiet way to lose sales, and most brands don't even realize it's happening.
Your bestselling style sells out of medium and large by mid-November. But you've still got smalls and XLs in stock, so on paper it doesn't look like you're out of stock. Except you are, for the majority of your customers.
How many people came to your site, loved the product, couldn't get their size, and left? You'll never know, because that's not tracked anywhere. But it happened. A lot.
Are your size curves actually reflecting what your customers want to buy, or are they based on old assumptions, supplier minimums, or what you've always done? And when you wanted to reorder a winner, were the money sizes already gone?
Size problems are almost invisible in your reporting. But they cost you real revenue and create real frustration for customers.
3. Planning Assumptions
Every plan you make relies on assumptions. You assume a certain level of demand. You assume customers will accept certain price points. You assume you can hit a certain margin. You assume a realistic growth rate.
The post-mortem is where you go back and check: which of those assumptions were right, and which ones were quietly sabotaging you?
Most planning problems don't happen because someone made an obviously bad call. They happen because someone made a reasonable assumption back in March, and then nobody ever questioned it again, even when the market shifted or early trading showed something different.
4. Critical Path and Delivery Timing
Here's something worth thinking about: "on time" and "well timed" are not the same thing.
Maybe everything arrived when it was supposed to. But did your hero products land early enough to get some traction before peak got crazy? Or did they show up in early November when you were already firefighting, and never got the attention they deserved?
Did anything arrive late and completely miss its moment? And looking at your overall timeline, was there any breathing room at all? Or was the whole thing so tight that one supplier delay threw everything else off?
When you're building the critical path, a tight schedule looks efficient. Everything lines up perfectly on paper. But when you're actually in peak, that lack of flexibility becomes a real problem. There's nowhere to maneuver. Nothing can be brought forward. No buffer if something goes wrong.
5. Supplier Constraints
This is one of those unglamorous topics that has a huge impact on what you can actually achieve during peak.
Were your supplier minimums a problem? When you spotted a bestseller and wanted to reorder, was it theoretically possible but practically impossible because of lead times?
Could you have topped up stock on winning lines, or were you stuck because your supplier needed 16 weeks and you had 6?
This is where the gap between what you should do and what you can do becomes painfully obvious. The missed opportunities are real, but so are the constraints.
6. Cashflow and Missed Opportunity
This one's uncomfortable to dig into, but it's worth it.
How often during peak did you see a product flying and think "right, we need to get more of that in," only to realize you couldn't because all your cash was sitting in stock that wasn't shifting?
Did slow movers from Q2 or Q3 block you from chasing bestsellers in November? Did you push deliveries back or cancel orders entirely, not because the demand wasn't there, but because you had to protect your cashflow?
Here's what a lot of brands don't realize: missed sales aren't always about product or demand. Sometimes they're about where you put your money six months ago, how long it stayed tied up, and whether you left yourself any breathing room to capitalize on what was actually working.
7. Pricing
The pricing calls you make at the beginning of a season have this annoying habit of following you around all the way to January.
Were your initial price points right, or did you price yourself out of the market (or leave margin on the table)? When you promoted, did it work to protect profitability, or did it just erode margin? Were your markdowns strategic and planned, or were you scrambling to shift stock reactively?
When margin disappoints, everyone points at the discounting. And fair enough, aggressive promotions do impact profit. But the real story usually starts earlier. If your opening prices were wrong, or you positioned yourself poorly against competitors, or you didn't leave space for sensible tactical offers, those problems were already there. Discounting just forced you to acknowledge them.
8. Competition and Market Shifts
Here's the thing about markets: they don't pause while you're busy executing your carefully laid plans.
Maybe a competitor suddenly shifted their pricing strategy in October. Maybe customer demand moved in a direction you weren't expecting. Maybe there were little signals earlier in the season that things were changing, but you were too focused on getting deliveries in to notice them.
Part of a good post-mortem is figuring out what was actually in your control and what wasn't. Sometimes performance issues come down to external market shifts that nobody could have predicted. But sometimes, if you're really honest, those shifts weren't totally invisible. The signals were there, you just missed them or couldn't do anything about them quickly enough.
9. Marketing and Stock Alignment
You know what's a terrible use of marketing budget? Driving loads of traffic to a product you can't actually fulfill properly.
Think about your campaigns during peak. Did they line up with stock depth and size availability, or did you create demand you couldn't meet? Did a well-performing email or social push accelerate sales faster than your inventory could handle? Did you start promoting certain ranges too early, before you had the stock in place to support the interest?
This problem's become really common, especially as digital marketing lets you turn things on at speed. Marketing does its job (drives awareness, clicks, interest), but if the stock situation can't support that demand, you've just paid to frustrate customers and leave money on the table.
Why now matters
If you're going to do a post-mortem (and you should), do it now while everything's still sharp in your mind.
Right now, you remember exactly why certain calls were made. You remember the constraints, the conversations, the moments where you thought "this isn't ideal but it's the best we can do." You remember what worked smoothly and what felt like you were constantly fighting against.
Leave it a few months and all of that detail starts to fade. Memory becomes guesswork. You lose the context. And the chance to genuinely learn from what just happened quietly disappears.
Using these learnings for 2026 (even if planning is done)
Here's something I hear all the time: "We've already done next year's plan, so there's no point doing a review now."
But that's backwards thinking.
A good post-mortem should absolutely feed into your 2026 plans, even if they're already underway or done. Actually, especially if they're already underway, because you've still got time to adjust things before it's too late.
Maybe that means changing your size ratios based on what you've just learned. Maybe it's shifting budget between categories. Maybe it's building in more flexibility so you're not boxed in again. Maybe it's rethinking how cash gets allocated so you've got room to react when opportunities show up.
Good plans aren't static. They evolve as you learn more. Treating them as unchangeable just because they're written down is how you end up repeating the same problems.
When an external view helps
You know your business inside out. That's valuable. You understand the context, the history, the constraints that aren't obvious to outsiders.
But being that close can also make it harder to see the patterns. You're so deep in the reasons why things happened that it's difficult to step back and see what actually needs to change.
That's where an external perspective helps. Someone who can look across the whole commercial setup (planning, range building, supply chain, pricing, marketing, trading) without being invested in the original decisions. Not to tell you what you don't know, but to help you see what you might be too close to spot.
Don't waste what peak just showed you
Peak has just handed you a load of valuable information. It's in your numbers, in the frustrations you felt, in the constraints that stopped you doing what you knew you should do.
A proper post-mortem captures all of that and turns it into something actionable. Into real changes for 2026, rather than just hoping things will somehow be different next year while doing roughly the same thing.
If you want next peak to feel less reactive and more controlled, this is the work that gets you there. And it's worth doing now, while it's all still fresh and the lessons are obvious.
If you'd like support working through a proper post-peak review that covers the full commercial picture (not just what sold and what didn't), feel free to reach out. January's usually the best time for this kind of work.
TLDR: Key takeaways
Peak trading doesn't create problems, it reveals them. Most issues that surface during November and December stem from decisions made months earlier in planning, buying, and range building.
A proper post-peak post-mortem examines the full commercial picture beyond just product performance, including
size availability
critical path timing
supplier constraints
cashflow allocation
pricing structure
competition
marketing alignment
Conducting this review in January while memory is fresh allows brands to feed learnings directly into 2026 planning, even if plans are already underway.
Common hidden problems include cash tied up in slow stock blocking bestseller repeats, size curve gaps causing invisible lost sales, tight critical paths removing flexibility, and marketing driving demand that stock levels can't support.
The goal is connecting peak results back to root causes rather than repeating the same patterns with different products.