Unreserved inventory, or non-guaranteed inventory, unlike guaranteed inventory, encompasses ad inventory that is not exclusively reserved or earmarked for a specific advertiser. In the case of unreserved inventory, there are no expectations regarding a minimum number of impressions for an advertiser, as there are no specific deals or arrangements for the particular inventory. Occasionally, industry professionals use unreserved inventory interchangeably with non-premium or remnant inventory, indicating that publishers could not successfully sell certain ad impressions through their programmatic direct deal channels.