How did category sales at each retailer fluctuate over the year?
Figure 2a: Estimated number of items sold by category at eBay. "1x" means "1x the amount of the smallest category (Toys & Games) in February, 2018." In other words, if Toys & Games sold 100 units in February 2018, that would mean Sports & Outdoors sold 155 units in the same month, and 180 units in March, according to Edison Trends.
Sales at eBay have remained largely steady throughout the year, with the biggest exception of December, where the number of Home & Kitchen items eclipsed those of both Tools & Home Improvement as well as Sports & Outdoors. Overall, most categories experienced a bump during the holiday season as people purchased gifts for their loved ones except for Automotive, which saw a decline in sales during the holiday months.
Interestingly, there was also a bump in sales during the month of March for many eBay categories, most notably in Electronics & Accessories, Clothing & Accessories, and Automotive. Throughout these bumps, Electronics & Accessories maintained its lead as the highest selling single category, with Clothing & Accessories close behind.
Figure 2b: Estimated number of items sold by category per month at Amazon. "1x" means "1x the amount of the smallest category (Automotive) in February, 2018," according to Edison Trends.
At Amazon, proportions of categories, relative to each other, remained steady for most of the year but saw large fluctuations during the holiday months especially in Home & Kitchen, Electronics & Accessories, and Toys & Games. Just as in eBay’s numbers, although less so, there was a jump in sales among many categories during the month of March. There’s also a bit of a jump in sales around July, most likely due to Amazon’s annual Prime Day. The biggest jumps in sales during Prime Day can be seen in Books, Electronics & Accessories, Home & Kitchen, and Software & Mobile Apps. Overall however, Books remains Amazon’s top selling category month over month.