Premium inventory is a term used in the context of online advertising to refer to high-quality and high-performing ad inventory that is in high demand by advertisers. Premium inventory can include a wide range of ad formats, placements, and targeting options, and can be located on a variety of websites and apps. Premium inventory is typically associated with high-traffic and high-engagement websites and apps, and can provide advertisers with access to a large and engaged audience. Premium inventory can also be beneficial for publishers and platforms, as it can provide a more predictable and stable source of revenue, and can help to maintain and grow relationships with key advertisers. Premium inventory can be sold on a variety of terms, such as cost-per-click (CPC), or cost-per-action (CPA), and can be an important part of an advertiser's media planning and buying strategy.