Global real-time bidded (RTB) media inventory grew by 61% year-over-year in Q4 2012, per study results from Accordant Media. While a healthy rate of growth, that 61% increase represents a slowdown from Q3′s 88% year-over-year rise, Q2′s 128% surge, and Q1′s 120% jump. The Q4 slowdown can be largely attributed to a waning growth rate in North America (41% in Q4 versus 62% in Q3). In turn, that is due in large part to the US, which held 47% share of the global inventory. The US’s inventory grew by 76% in 2012 overall, compared to 101% growth globally. In Canada, meanwhile, supply surged in Q4 to its highest levels for the year.
Focusing on the North American market, the study finds that in Q4, cost-per-thousand impressions (CPMs) declined by 9% year-over-year, reversing Q3′s 2% rise. While edging up by 1% year-over-year, click-through rates were down 12% from Q3. Read the rest at MarketingCharts.