IAB Podcast Upfront: Amazon DSP Unites SiriusXM, Spotify, Acast and iHeart Supply

The 2026 IAB Podcast Upfront framed podcast advertising around four forces — the creator, the surface, the pipe and the metric — as the industry described a medium that no longer lives in a single feed, according to an IAB recap published September 25.

Content now moves through RSS, HLS, YouTube, Spotify video, Rumble, FAST, VOD, social clips and live events, with audiences picking whichever surface fits the moment. What holds that audience together is the creator, IAB’s Jason Adamski wrote, and publishers are building businesses around that relationship in very different ways.

Amazon’s move to pull major podcast supply into its demand-side platform was among the day’s clearest buying-side shifts. SiriusXM, Spotify, Acast and iHeart became buyable together inside Amazon’s DSP, with video inventory described as next. Publishers also serve ads dynamically on YouTube via Google’s ad server and are building single distribution points into Apple, Spotify, YouTube, Tubi and FAST.

Every format has a job, the Upfront argued. Clips drive discovery — 81% of listeners said a clip led them to a specific episode. Audio builds trust and carries the lowest skepticism of any format. Video captures attention and drives action. New research cited at the event showed that adding visuals to the same audio ad lifted unaided awareness from 39% to 68%.

HLS is emerging as a path to bring programmatic creative closer to host-read quality, though only 4% of the top 500 shows are HLS-enabled today, the IAB recap said. That gap underscores how far delivery standards still have to travel even as buying pipes consolidate.

For readers following audio and video podcast ad markets on Podcasts, measurement remains the unresolved fourth theme. Difficulty measuring ROI is still the top reason buyers hold back on digital audio. YouTube’s shift to a zero-second view inflates counts by roughly 1.8x, while Spotify’s thirty-second play and Apple’s HLS reach count differently — unstable definitions, not missing numbers.

Strategies on the creator side diverge: some companies concentrate on a small roster of top talent for scale and chart position, while others argue that the right 100 listeners beat 100,000 downloads and chase niche audiences that command premium CPMs. Taken together, the Upfront described an ecosystem with more momentum than ever — and a 2027 path that hinges on shared definitions for clips, views, plays and sessions so buyers can invest with confidence.