Global real-time bidded (RTB) media inventory continued to grow in Q3, up 88% year-over-year and 29% quarter-over-quarter, according to an October report from Accordant Media. While this was a slowdown from Q2’s 128% year-over-year growth rate, it shows advertisers and publishers venturing further into the RTB market. Q3’s growth was fueled largely by increased RTB adoption in Western Europe, Brazil and Australia, with North America’s Q3 growth rates (+62% year-over-year; +21% quarter-over-quarter) trailing the global average.
In particular, the report cites France, Brazil, Germany, Italy, and Mexico as healthy markets for real-time buyers and sellers.
CPMs, CTRs, Also Up in North America
Focusing on the North American market, the study finds that in Q3, cost-per-thousand impressions (CPMs) reversed Q2’s 8% year-over-year decline, rising by 2% over Q3 2011, and by 7% over Q2. Accordant Media suggests that this may be due to supply and demand forces at work, given slower growth in inventory in Q3.
Click-through rates also grew in Q3, jumping 33% year-over-year, and by a more muted 5% quarter-over-quarter.
Primary Ad Units Still Dominate; Others Grow More Quickly
The RTB display market remains focused on 3 units, with the 300×250 (37.7%), 728×90 (37%), and 160×600 (16.3%) sizes collectively accounting for 91% of the market. Even so, other unit sizes are seeing more interest.
For example, the 300×600 size, while accounting for just a minute 0.2% share of the market, saw 408% quarter-over-quarter growth in impressions. This compares to a growth rate ranging from 23-31% for the primary units. The remaining unit sizes (“all others”) made up 8.8% share of total impressions, increased in volume by 60% from Q2.
Mobile Inventory Becoming More Valuable
The Accordant Media report also finds that mobile inventory is becoming more productive. Looking at indexed conversion rates (calculated as attributed conversions / impression), the study finds mobile only 15% behind standard display. Video sites actually had a higher indexed conversion rate than standard display, but with far higher CPMs, were not as effective.
An August study from MoPub found increased demand for mobile RTB inventory in H1: advertiser and demand-side platform demand for mobile ad impressions (both in-app and otherwise) through RTB rose from 0.4 bids per impression request in January to 1.6 in June, with a peak of 1.7 in May.
About the Data: The Accordant Media report utilizes aggregated data sets to showcase year-over-year and quarter-over-quarter trends. During Q3, Accordant MediaÊ¼s programmatic media buying system bid on ad impressions across nearly 425,000 sites spanning display, video and mobile inventory on behalf of leading media agencies and in-house marketing teams.