I’m an Amazon seller looking to expand to Walmart. I have some products in a niche category, and I want to see how the market looks. Some competitors are already selling there, but I can’t find sales data anywhere.

How do you estimate Walmart sales volume? For example, I’d like to know seasonal trends — how did certain products perform during May–July last year, or during Q4?

Most Amazon-focused tools seem to have very little data on Walmart. Any suggestions?