Why promotions empty the shelves — and how to stop it

Promotions October 2026 · 6 min read

In short

Most promotion stock-outs are a planning gap, not bad luck.
Marketing and supply chain usually plan on different calendars.
The fix starts with one shared plan and an estimate of the extra demand.

A promotion is a bet that more customers will walk in. Marketing builds the excitement, the price drops, and by Wednesday the best-selling item is gone. The customers who came for it leave with nothing, and the offer you paid to advertise quietly turns into a lost sale — and sometimes a lost customer.

It feels like bad luck. It almost never is. When a promotion runs out of stock, there is nearly always a predictable chain of events behind it.

The chain of events behind a stock-out

Marketing agrees the offer, the price and the dates with the supplier or internally.
The campaign is designed, approved and printed or scheduled.
Supply chain hears about it — sometimes weeks later, sometimes only when sales spike.
Someone estimates how much to order, usually from 'the last time we did something similar'.
The supplier needs more notice than is left, so the order is small, late, or both.

Notice that nobody in this chain did anything wrong. Each team did its job. The failure sits in the gaps between teams.

Three reasons the estimate is wrong

The last promotion wasn't the same

'Last time we sold three times as much' is a reasonable starting point, but last time may have had a different price, a different week, a different weather forecast or a competitor running its own offer. The same discount can behave very differently in different conditions.

Every store is treated alike

A city-centre store and a rural store don't respond to an offer the same way. One national number hides this, so some stores run out on day two while others are left with pallets.

Cannibalisation and halo are ignored

A promotion on one product often takes sales from a neighbouring product — and sometimes lifts a related one. If you only plan for the promoted item, the neighbours end up wrong in both directions.

A calmer way to run a promotion

Bring supply into the plan on day one, not after the poster is printed.
Estimate the extra demand for the offer, store by store, instead of one number for everyone.
Agree who owns the decision to add stock, and by what date.
Look at the neighbouring products as well as the promoted one.
Watch the first days of the offer closely. If it's running ahead of plan, you can still react.
After it ends, record what really happened so the next offer starts smarter.

A simple test for your own business

Pick your last three promotions. For each, answer: When did supply chain first hear about it? How much extra demand was expected, and how much actually came? Which stores ran out first? If those answers are hard to find, that's your starting point — not a new tool, but visibility.

The point of all this

None of this needs to be complicated. It needs the offer, the forecast and the stock to live in the same picture, so the people who run the promotion and the people who supply it are looking at the same thing. That is the idea behind planning promotions and supply together — and why we built the Promotions and Campaigns modules to work side by side.