They are the owners (or were because I have not read an SCD for quite a while) of Sports Collectors Digest and their Standard Catalog,
I've written quite a bit about this in the past for my old Sports Collectors Daily column and don't want to say anything more right now. I'll probably save any comments for an upcoming GTS column
https://www.forbes.com/sites/tonysil.../#63b1af5b4355
Regards
Rich