Ad spend on digital audio – Audio Streaming and Podcasts – is now nearly on par with Terrestrial Radio, after being just a third of it three years ago.
That’s according to a new Digital Audio Advertising Spend and Pricing product being offered from Standard Media Index.
The increase is being driven in great part by ad spend on podcasts, which grew 68% year-over-year in 2021 and now account for 8% of all Digital Audio spend.
The new offering, which is based on actual spend data from SMI’s pool partners of major holding companies and large independent agencies, representing 95% of all US ad spend, also shows that Podcasts now lead all media categories in CPMs at an average of $26, topping even premium video ads on OTT, which have an average CPM of $25.
“Podcasts are not a new format, but over the last several years and especially during the pandemic, consumer consumption has accelerated and advertisers are following their audiences to the channel,” SMI President Ben Tatta said. “Due to their highly-contextual ad formats, such as custom/native spots and host read-ads, Podcasts are commanding heavy premium CPMs, with some such as Ladygang and Shattered Glass at $96 and $63 respectively.”
Among the other findings:
- While Terrestrial radio ad spend grew 14% YOY in 2021 coming out of the pandemic, In-Stream Digital Audio grew 43% during that time
- The average CPM for Digital Audio overall is $17
- Among the Top 3 audio owners, Spotify gained the most share of total audio dollars in 2021, up 9% since 2017
- Podcast advertising spend growth is driven by host-read placements (+199% YOY) and audio spots (+74% YOY)
- National advertisers of all types are gravitating to Digital Audio, with categories such as CPG, Technology, Financial Services and Entertainment/Media representing a larger share of spend versus Terrestrial Radio.



