Publishers and SSPs are upgrading their technology as buyers demand outcomes, performance insights and impression-level data, according to a trend analysis published by AdMonsters. The report identifies three sell-side forces set to define 2026: vertical video as a primary engagement driver, AI-powered sell-side decisioning, and programmatic transparency as a competitive differentiator.

Vertical video becomes the open web's front door

Short-form vertical video will not merely enhance publisher experiences in 2026 — it will define them, the analysis argues. Some leading publishers are already rebuilding homepages and article templates around immersive, swipe-first video streams.

The shift will change how users enter the open web, with vertical clips acting as a "front door" that funnels audiences into news, evergreen content and commerce experiences. Early adopters, including The New York Times, are focused on creating and curating vertical video across multiple content verticals as part of a multi-format strategy. Emerging tech solutions will lower the barrier to entry for publishers of all sizes.

Two additional forces will push the format up the value chain. First, the rise of AI-generated misinformation and deepfakes will steer advertisers toward brand-safe vertical environments controlled by trusted publishers — elevating vertical video from a format to a standalone premium channel. Second, attention and engagement are becoming the core KPIs for digital storytelling, and AdMonsters expects CMOs to carve out dedicated budgets for this inventory.

The result: the open web will compete with walled gardens on the same creative canvas, with one advantage — credibility.

Sell-side decisioning becomes the performance battleground

The next leap in programmatic efficiency will come not from curated packages but from smarter sell-side decisioning, the report states. AI and machine learning now let SSPs analyze troves of nuanced first-party publisher data more efficiently.

Even amid signal loss, SSPs can train models on desired campaign outcomes, enabling proactive and effective decisioning. These systems allow partners to build audiences, make and optimize bidding decisions before sending requests to demand partners, create and troubleshoot deal performance, and gather bidding insights.

SSPs are evolving from simple access points into real-time decision engines that determine which impressions to surface, which demand paths to prioritize and which low-quality supply to filter out before the auction begins. The shift creates a cleaner, higher-signal supply layer by default, delivering performance gains to buyers without manual curation work.

As identity erodes, decisioning becomes a new form of addressability — powered by context, intent and quality scoring rather than user IDs. AdMonsters notes that economic uncertainty is triggering waste-related alarms among buyers, making intelligent upstream choices before a bid is placed exceptionally valuable.

Transparency turns into a measurable advantage

Programmatic transparency has long been treated as hygiene. In 2026, it will become a competitive moat, the analysis predicts. As marketers gain clearer visibility into how impressions are sourced, scored and priced, transparency will correlate directly with lower media waste and higher ROI.

Buyers will increasingly abandon ambiguous supply paths in favor of partners who can show, not tell: no MFA sites, no hidden fees, no black-box optimization. Citing ANA research, the report points out that 99% of programmatic spend went to environments with low risk to buyers, and that MFA sites lost significant market share in 2025. The sell-side success stories of 2026 will come from publishers that communicate the quality of their inventory effectively.

The rise of AI raises the transparency bar further. Marketers will insist on explainable automation that surfaces why certain impressions won and how decisions were made. AdMonsters expects a two-tiered market: systems built on radical clarity will rise, while opaque platforms lose relevance in budget cycles driven by accountability. Transparency will evolve from a compliance requirement into a performance driver.

Broader market implications

Sell-side innovation will influence the entire ad market, the report concludes. Advertisers will increasingly recognize the value of the open web and build closer partnerships with publishers and SSPs. As tech solutions see wider adoption, a growing share of publishers will be positioned to capitalize on these trends — translating into more revenue for quality publishers of all sizes.

Source: AdMonsters (https://www.admonsters.com/video-engagement-sell-side-decisioning-transparency-the-publisher-advantage-in-2026/) / Source: hollywoodreporter.com (https://www.hollywoodreporter.com/business/business-news/inside-new-york-times-vertical-video-strategy-watch-tab-1236420172/)