Question about Branding and Listing on Amazon

Hello Amazon Sellers,

I have a question regarding product branding and listing on Amazon, and I was hoping to get some insights from the community.

I recently noticed a product listed on Amazon under the brand name “DEF,” but the actual brand of the product is “ABC.” This got me thinking: if the original brand is ABC, are other sellers allowed to list the same product under its original brand name?

I find it puzzling why a seller would choose to create their own brand for a product that already has an established brand name. Can anyone shed some light on why a seller might do this? Additionally, with three sellers currently listing under the brand name DEF when the actual brand is ABC, I’m curious about the implications of listing the product under its original brand. Can I also list it as DEF as well? will the seller kick me off the list? I see three sellers with DEF.