Navigating connected TV’s inventory share maze
If you’ve spent time in the trenches of programmatic CTV buying and selling, then you’ve probably found yourself deep in app-ads.txt files, counting inventorypartnerdomain (IPD) lines and wondering how things got so complicated. I reviewed 12 major EPGs, FAST platforms, and vMVPDs — and found an average of 54 IPD lines per platform. Some had over 100. As FAST channels multiply and publishers reclaim monetization control, programmatic buyers face a growing challenge: verifying who’s selling what, and through whom. What was once a simple tool has become a tangled web. Let’s break down what those IPD lines actually mean, how the CTV value chain works, and how buyers can navigate it strategically — without overpaying or getting lost in the maze. Understanding inventory partners: Key players in the CTV ecosystem At first glance, accessing CTV content seems straightforward. In reality, the more content a platform offers, the more expansive the ecosystem required to support it. Much of that ecosystem is now just as likely to take a portion of ad inventory to monetize themselves as they are to charge a fee for their services. That’s where inventory share comes into the picture. The clearest example is the way that local affiliates of the big 4 broadcast networks operate: the affiliate monetizing 2-3 minutes of ads per hour and the network controlling the rest. In streaming, the same basic model extends to the vMVPDs — but it doesn’t end there, and the Interactive Advertising Bureau (IAB) guidance is trying to catch up to this evolution. The complex web of inventory share partners: Mapping the CTV value chain Content owners The element of the CTV ecosystem closest to viewers is the content itself. Besides major media companies like Disney and NBCUniversal, lower-profile players like Fremantle and Lionsgate also have expansive libraries. According to Jounce Media‘s 2024 research, 30 of the top 100 CTV sellers are content owners. The share of inventory controlled by content owners varies widely, with estimates as low as 20% for emerging companies and as high as 80% for the industry giants. These content owners have a credible claim to exclusivity across all major streaming platforms. This makes them essential partners for buyers seeking broad reach. Channel developers Many content owners lack their own streaming platforms and must find alternate ways to reach viewers. Enter channel developers, who may take a share of inventory in return for handling curation, scheduling, licensing, and distribution. Notable channel developers include Navio Networks and OTTera. Content distributors These are the apps that you interact with directly and names that you know. These include FAST platforms like Tubi, vMVPDs like Fubo, and EPGs like Samsung TV Plus. These platforms are likely to control substantial portions of ad inventory for their own monetization — often including inventory from the walled gardens. Platform developers In some cases, the streaming platform doesn’t handle its own development but relies on a specialist to build the infrastructure. Today this is a small but critical part of the ecosystem as costs to build streaming apps in-house are a major barrier to entry. Platform developers include companies like Endeavor Streaming and Future Today. Original equipment manufacturers (OEMs) Most major apps run on every brand of TV (or aspire to). This is where the OEMs come into our ecosystem; they’re names that you know like Roku and Vizio. They too control a substantial portion of inventory for their own monetization. Tech providers An overlooked layer of inventory share is the various tech providers that are necessary to get ad requests in front of buyers and serve ads to viewers. The offerings here are growing, but common services include server-side ad insertion (SSAI) and ad serving. This includes companies like Amagi and Wurl. Management services An emerging category is that of “management services,” which can exist at almost any level above–offering help with tech stacks, monetization, and ad ops. This category — along with that of tech providers — is growing in line with the complexity of getting programmatic ads to market. Examples here include companies like TVIQ, CTV Buyer, and GoGo CTV. Strategic approaches to CTV buying and verification None of this is to say that CTV buyers should stop going directly to the big-name platforms — those IOs and PMPs are the cornerstone of many sound media plans. However, navigating this complex ecosystem requires a strategic approach: Expand your definition of “direct” First, it’s important to expand the definition of “direct” to include partnerships with content owners and tech/service providers. Factors like campaign size, targeting specificity, scope of whitelist, CPM goal, and competitiveness of inventory should all factor in when deciding how far you tread into the inventory share maze. Vet your inventory sources Everyone wants “unique and exclusive inventory” — both sellers and resellers know that — and the opaqueness of inventory share is an all-too-tempting selling point…even when partners don’t actually have inventory share. Many of those with legitimate inventory shares recognize this challenge and have made a concerted effort in the last 12-18 months to get their IPD lines placed. At the very least, the presence of IPD lines lets you know that there is an officially recognized relationship. You’re better off restricting to inventory with IPD lines than taking a potential partner’s word on inventory share. Get your IPD lines in place If you’re an inventory share partner, it’s probably in your best interest to get IPD lines ready to go. This is pushing ahead of the most recent IAB guidance, but it makes it easier for supply-side platform (SSP) and DSP partners to vet your inventory and whitelist it. Eventually, the IAB guidance will catch up and hopefully provide all of us a more robust way to keep track of where in this inventory share maze these partners are located. (Selfishly, I’d also love a requirement that IPD partners disclose how much share they actually control.) Finding your path through the maze As the CTV ecosystem continues to evolve, here’s what buyers need to remember: Looking ahead:...
