Stockout

A stockout (also called *out of stock*) happens when a product is not available for sale at the time and place a customer looks for it. It can occur on the shelf at the point of sale, in a distributor's warehouse or in an e-commerce fulfillment center. It is not just running out of goods: it is losing a sale that was ready to close and, worse, pushing the customer toward a competitor.

Stockouts are usually measured as a percentage of SKUs out of stock over the total that should be available, at a given point of sale and moment. In brick-and-mortar retail, international studies put the average on-shelf stockout rate at around 8% (FMI, GMA and CIES study by Gruen, Corsten and Bharadwaj, 2002), a figure that is usually taken as an industry benchmark, not as a guaranteed result.

Avoiding stockouts depends on real-time inventory visibility across the chain: knowing what you have, where it is and when it moves. It is part of what Trazzo tracks, with product traceability from origin to final delivery.

Why a stockout costs more than it seems

A stockout is not an isolated event: it drags along visible and invisible costs. The visible cost is the lost sale of the out-of-stock product. The invisible one is what happens next: the customer buys a substitute brand (and may not come back), abandons the entire cart in an online store, or associates your brand with poor availability. In consumer goods, the FMI, GMA and CIES study (2002) shows that when faced with a stockout the shopper does not wait: around a third go to another store and one in four buys another brand. That is why stockouts erode the fill rate, OTIF and, in the long run, loyalty.

How it is measured

The base metric is On-Shelf Availability or its inverse, the stockout rate. It is calculated as out-of-stock SKUs over expected SKUs, at a specific moment and place. It helps to distinguish two levels:

• Shelf stockout (front): there is stock in the backroom, but it never reached the shelf. It is a replenishment and execution problem, very common in retail.
• Warehouse stockout (back): there is simply no product in the store or in the distribution center. It is a demand planning and supply problem.

Most frequent causes in Latin America

1. Weak demand forecasting: underestimating peaks (national holidays, end of month, promotions) leaves you without goods right when sales are highest.
2. Poorly calculated safety stock: if the buffer does not account for the real variability of the lead time, any supplier delay creates a stockout.
3. Phantom stockout: the system says there is stock, but it is not on the shelf (shrinkage, theft, counting errors). The book inventory lies.
4. Links in the chain without visibility: if you do not know in real time what each distributor or branch has, you react too late.

A concrete example

A consumer goods company in Argentina launches a soft drink promotion for a long weekend. The sales team projects normal demand, but the heat and the holiday drive sell-out through the roof. By Monday, 18% of the promoted SKUs were out of stock at the main chains: the promotion was paid for, but a good share of the sales went to the competitors that did have full shelves. The problem was not marketing, it was availability: without visibility of daily sell-out by branch, replenishment arrived two days late.

Stockout vs overstock: the balance

The stockout has an opposite that is just as costly. Restocking too much so you never run out of anything ties up capital and creates expirations and obsolescence. Inventory management looks for the middle ground between both extremes.

How to prevent it

Prevention combines data and processes: demand forecasting based on real history, safety stock calculated from variability (not eyeballed), automatic replenishment policies by reorder point and, above all, real-time inventory visibility at every link. When traceability covers everything from origin to the last mile, stockouts stop being discovered when it is already too late and start being anticipated.

Common mistake: blindly trusting the system's book inventory. The phantom stockout (the system says 12 units, the shelf has 0) is one of the most expensive because nobody restocks what the system believes is there. Shelf audits, cycle counts and traceability by SKU and lot are the only way to close that gap between the data and reality.