Fill Rate
The percentage of available advertising inventory that is successfully sold and filled with paid content.
Fill rate is a key performance metric for advertising networks that measures the percentage of available advertising inventory that is successfully sold and filled with paid advertising content. A fill rate of 100% means every available advertising slot was filled with a paying advertiser's creative; a fill rate of 60% means 40% of available slots went unfilled (typically displaying house ads or default content).
For retail media networks operating programmatic advertising, fill rate is directly influenced by the number and quality of demand-side partners connected to the network's SSP, the floor price set for inventory, the attractiveness of the audience data available, and the competitiveness of the inventory in the market. Networks with strong first-party audience data and high-footfall locations typically achieve higher fill rates because they are more attractive to programmatic buyers.
Improving fill rate is a primary revenue optimisation goal for retail media operators. Strategies include connecting to more DSPs, reducing floor prices during low-demand periods, improving audience data quality, and packaging inventory into premium deals that guarantee fill. The Adflux programmatic SSP connects retailers to 35+ global DSPs to maximise fill rates, with real-time reporting on fill rate by screen, location, and time period.