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The Daily Review


Low Product Availability: A Challenge For Amazon Vendors

How has COVID-19 affected product availability on Amazon?

Product availability is a challenge for vendors this year. We’ve heard from some of our Amazon Vendor customers that their products keep going out of stock on Amazon, leading to lost sales.

As we discussed in our previous post, 2020 has been a record-breaking year in terms of sales and also reviews on Amazon. Exceptionally high demand has thrown a wrench into Amazon’s sales forecasting algorithms and has led to delayed purchase orders for products from vendors. Along with increased consumer demand, however, we’ve seen widespread disruptions in factories and fulfillment centers that led to shortages of inventory for many in-demand products. It's no wonder that many vendors have questions. So, let’s take a look at what’s going on this year with availability on Amazon. 

Tracking Product Availability

Reviewbox tracks the availability status of products on Amazon. For this analysis we tracked more than 3800 products that are sold by Amazon in six major Product Categories. 

Product Category:

  • Grocery & Gourmet Food
  • Cough & Cold Products
  • Networking Electronics 
  • Patio, Lawn & Garden
  • Pet Supplies
  • Home & Kitchen

Amazon uses several different terms to refer to product availability. We grouped them into two categories for our analysis. Here, In Stock includes the ‘in stock’ category for items sold by Amazon as well as those sold by third-party sellers. All other stock levels, including 'unavailable' and 'temporarily out of stock', were considered Out of Stock for our analysis. 

The proportion of products In Stock on Amazon has decreased over the course of 2020, as shown in Figure 1.

percent of items in stock on Amazon over 2020
Figure 1: Percent of products In Stock on during each week of 2020. January 1 = Week 1 and July 15 = Week 29.


Cough & Cold products as well as Grocery & Gourmet Foods were both hit hard, and early, by a huge increase in demand from consumers. Stock levels for Cough & Cold pharmacy products dropped to less than 20% twice during March. Even though shipments of new inventory were being shipped to the Amazon fulfillment centers, supplies could not keep up with the demand. Even during the summer, barely 50% of products in this category were in stock. Similarly, the availability of Grocery and Gourmet Food decreased to 36% by mid-April. Stock levels have rebounded somewhat during the summer, but they remain depressed because of record-breaking Amazon sales in this category. 

The availability for Home & Kitchen, Networking Electronics, and Patio, Lawn & Garden items has been declining steadily through the first half of the year. The initial reason for this appears to be supply chain disruptions and factory closures, especially for products that are made in China. The interesting thing to note in these categories is that the availability has remained low despite new shipments coming in. Various industry observers have noted an increase in demand for furniture and home improvement projects from customers stuck at home during COVID lockdowns.

Pet Supplies have not experienced the big fluctuations in availability seen in other categories, but the in stock percentage was already relatively low at the beginning of the year. It's possible that even though Amazon has sold out, some of these items have been picked up by 3P sellers. 


When Amazon is Out-of-Stock, 3P Sellers Step In

Even though a product is listed as In Stock, Amazon itself may be out of stock and the buy box may be owned by a third-party seller. We looked at overall stock levels in July 2020 across all six of our product categories considered above. We found that, in fact, 12% of our products were only available from third-party sellers. Overall, only 41% of our products were in stock and sold by Amazon. 

percent of in stock items on July 15, 2020
Figure 2. Donut chart showing the percentage of product in each availability category, including In Stock, Out of Stock, Low Stock, and 3P ownership of the buy box across 3800 Amazon listings on July 15, 2020.


This year, manufacturers have to contend with inventory shortages at Amazon, as well as the usual competition from 3P sellers, if they want Amazon to maintain control of the buy box for their products. 

Challenges for Amazon Vendors

It is clear that COVID-19 has hit Amazon hard. Along with the opportunity for rapid growth, there is also intense pressure to meet consumer demand. After all, you can’t sell the product if it is out of stock! 

Over the past few months, Amazon’s automated purchase orders have not kept up with sales. Manufacturers will need to work closely with Amazon to accurately forecast future sales of their products as we move into the holiday season and the winter months. Every Amazon Vendor should take precautions to keep their products in stock, including improving demand forecasting, partnering with sellers, or maybe even a hybrid strategy

At Reviewbox, we closely monitor your products on Amazon and other retail sites so you will know if your item is selling out of stock or if a 3P seller has won the buy box. Our upcoming Vendor Central integration will pull all your data together in one place for convenient monitoring and analysis. To find out more, visit