• by Gavin O'Malley , Staff Writer, September 6, 2018

Driven by consumers’ growing preference of app versus mobile browsers, mobile advertisers are increasingly leveraging in-app private marketplaces (PMPs).

That’s according to the latest Mobile Index from sell-side platform PubMatic, which identified some notable trends in the second quarter.

“We are continuing to see the rise of in-app at the core of programmatic ad spend,” Paulina Klimenko, SVP of corporate development at PubMatic, notes in the new report.

“As consumer engagement steadily shifts to mobile app environments, the potential for both publishers and advertisers to capitalize on this trend is huge,” said Klimenko.

Of course, ad spending is also shifting away from desktop video toward mobile.

From the second quarter of 2017 to the second quarter of 2018, mobile video ad spend increased by 239% -- including 688% year-over-year growth via apps, and 73% year-over-year via mobile web.

Overall, mobile ad spend increased by 25% from the second quarter of 2017 to the second quarter of 2018, PubMatic found.

Already representing more than half of mobile ad spend worldwide, in-app ad spend growth remained strong at 21%, year-over-year. The in-app expansion was primarily driven by a 47% annual growth rate via iOS, while Android rose 13%.

Year-over-year, mobile web eCPMs declined 16%, due to what PubMatic attributed to downward pricing pressure.

As advertisers continued to funnel ad budgets into mobile apps, in-app eCPMs rose 11%, year-over-year. Desktop eCPMs improved 5% during second quarter, year-over-year.

For its Index, PubMatic says it surveys some of the 12 trillion ad bids that its yield and data analytics team analyzes on a monthly basis.