Solved
SFDC Assets and Marketo Smart Lists
I want to build a list where anyone who DOESN'T own products XYZ will show up. However, when I build the list if there are 5 products and 4 of them don't include XYZ but the fifth one does, then it still pulls those people with the product into the list. Is there a workaround for this at all? Hoping I'm missing something obvious.