The players

Ad fraud and invalid-traffic prevention, built around a Traffic Quality Index (TQI) Score for every source.

ClearTrust's click-fraud and invalid-click protection for performance advertisers.

ClearTrust's publisher-side ad-quality and malvertising protection, delivered with one script tag.

Veteran consumer data company, owned by IPG since 2018 and now part of Omnicom.

Independent research firm whose ad-transparency reports have challenged platforms and verification vendors.

Attention metrics company scoring media placements on their likelihood to be noticed.

Europe's largest independent full-stack ad platform: DSP, ad server and publisher tools.

Berlin-based mobile measurement partner, owned by AppLovin since 2021.

European ad verification company, bought by Scope3 in 2024 and then by Peer39 in 2026.

Adobe's marketing stack: analytics, a CDP, a DSP and creative tools used by big brands.

Machine-learning ad buying company, taken private by Cadent in 2024.

China's e-commerce giant, whose Alimama unit runs one of the world's largest retail media businesses.

Amazon's ad arm: sponsored listings on the store, Prime Video ads, Twitch, and a DSP for the open web.

Amazon's demand-side platform, buying Prime Video, Amazon and open-web ads with shopping data.

Former Singtel-owned ad platform, acquired by Tremor (now Nexxen) in 2022.

Ad fraud detection focused on accuracy, used for lead-gen and affiliate traffic.

Not an ad company, but its privacy rules on iPhone reshaped mobile advertising, and it sells App Store ads.

Mobile ad giant whose AI engine AXON made it one of the most valuable ad tech companies.

The largest mobile measurement partner, telling app marketers which ads drove installs.

India's self-regulatory body for advertising content standards.

US trade group for brand advertisers, known for landmark studies on programmatic transparency.

Major US radio group (formerly Entercom) that went private after a 2024 bankruptcy.

One of the largest global affiliate marketing networks, including ShareASale.

Dutch digital advertising and casual games group, owner of the Improve Digital SSP.

China's leading search engine, whose ad business is shifting to AI-powered search and the Ernie models.

Media planning and buying software that combines a DSP with workflow tools for agencies.

Plumbing that connects many DSPs to many SSPs through one integration, owned by Criteo.

Location-based audience planning and buying platform, acquired by T-Mobile in 2025.

Deep-linking and mobile measurement company that routes people to the right place inside apps.

Software that runs many of the world's digital billboards, now including the Place Exchange SSP.

Converged TV advertising platform that acquired AdTheorent in 2024.

Runs cashback offers inside banking apps, using card purchase data to target and measure.

Curates brand-suitable YouTube channels for advertisers.

Mobile game ad network and mediation platform, owned by Zynga and therefore Take-Two.

Watchdog nonprofit campaigning for ad-industry transparency and against funding disinformation.

Go-to-market security company blocking fake clicks, fake leads and bots across paid marketing.

Major US billboard and airport advertising company, agreed to be taken private by Mubadala.

Click-fraud blocking for small advertisers, now part of CHEQ as CHEQ Essentials.

Comcast's self-serve platform letting smaller advertisers buy premium TV and streaming ads.

Audience measurement company for digital and TV, a long-time Nielsen rival.

Publisher-side ad quality and malvertising protection, used by major news sites.

South Korea's dominant online retailer, with a growing retail media business.

Commerce advertising company famous for retargeting, now centred on retail media for big retailers.

Criteo's platform powering sponsored-product ads for retailers' own websites.

Japan's largest internet ad agency, also running games and the ABEMA streaming service.

Publisher-quality intelligence that flags made-for-advertising and risky sites for buyers.

Japan's largest ad agency group, with a global network including Carat and Merkle.

European consent management platform that bought rival Sourcepoint in 2025.

Pre-loads apps on new phones for carriers and runs an in-app ad exchange (formerly Fyber and AdColony).

Sells ads across Disney+, Hulu, ESPN and ABC, one of the largest TV and streaming ad businesses.

Pioneering ad server bought by Google in 2008; its tech lives on in Google Ad Manager and DV360.

Leading ad verification company checking that ads are seen, safe and served to humans; being bought by Nielsen.

Data science consultancy specialising in marketing mix modelling.

Publicis Groupe's data and identity engine, with a DSP and retail media tools.

French ad server and SSP (formerly Smart AdServer) that absorbed Sharethrough.

The marketing-data arm of credit bureau Experian, providing audiences and identity resolution.

AI-driven ad testing platform for small and mid-sized publishers.

Independent advertiser ad server and creative platform, owned by Mediaocean.

Retail media network of Flipkart, India's biggest e-commerce marketplace, majority owned by Walmart.

Pre-bid fraud detection for ad exchanges, SSPs and DSPs, plus IP risk data.

Publisher monetization company running header-bidding stacks for mid-sized and large sites.

Comcast-owned ad server and marketplace that runs ads for much of premium TV and streaming.

Ad security and quality monitoring for publishers and ad platforms.

The largest ad business on earth: search ads, YouTube, and tools on both sides of the open-web ad market.

Google's publisher ad server and exchange, the market-leading tool at the centre of the US antitrust case.

Google's enterprise DSP for buying display, video, YouTube and CTV ads programmatically.

Contextual advertising company using computer vision to understand pages and images.

Clean-room software company acquired by LiveRamp in 2024.

Japan's second-largest advertising group after Dentsu.

Incrementality and causal marketing measurement startup.

French advertising group spun off from Vivendi and listed in Amsterdam in December 2024.

Programmatic DOOH platform acquired by Perion in 2024.

Bot-detection company (formerly White Ops) that helped take down major ad fraud schemes like Methbot.

The main US trade body for digital advertising, setting guidelines and lobbying for the industry.

European digital advertising trade body and steward of the Transparency & Consent Framework.

Standards body behind OpenRTB, VAST, ads.txt and sellers.json.

Cashback rewards company whose Ibotta Performance Network puts offers inside retailers' apps.

Independent identity provider whose ID5 ID helps publishers and buyers recognise users without cookies.

America's largest radio company and a top podcast publisher, owner of Triton Digital.

Canadian journey-advertising platform, formerly AcuityAds, listed in Toronto.

Partnership automation platform for affiliate, influencer and B2B partnerships.

European SSP owned by Azerion, serving publishers across Europe.

Large independent ad exchange and early header-bidding champion, privately owned.

Ad tech roll-up that bought MediaMath out of bankruptcy in 2023.

Data clean room pioneer that lets companies match data without sharing it; acquired by WPP in 2025.

India's first unicorn: a mobile advertising platform and owner of the Glance lock-screen business.

CTV ad-serving and measurement company acquired by Mediaocean in 2025.

Grocery delivery app with one of the largest retail media businesses, also powering ads for grocers.

Major ad verification company, taken private by Novacap in December 2025.

Former agency holding company (McCann, IPG Mediabrands, Acxiom) acquired by Omnicom in 2025.

Small ad tech company using AI to target audiences without personal data (IntentKey).

Engineering firm that built custom ad tech for others (and BidSwitch), acquired by Criteo in 2022.

CTV content-data platform acquired by Viant in 2024.

UK advertisers' trade body, known for its 2020 study on the programmatic "unknown delta".

TV and streaming ad measurement company challenging Nielsen as a currency.

The largest outdoor advertising company in the world: bus shelters, airports and billboards.

India's largest TV and streaming company, formed by merging Reliance's Viacom18 with Disney's Star India.

Supply-path research firm that maps the programmatic supply chain for buyers.

Global TV audience measurement and media intelligence company, sold to H.I.G. Capital in 2025.

Mobile and CTV ad marketplace known for high-impact creative formats.

API-based ad-serving infrastructure that retailers use to build their own retail media networks.

Mobile measurement and data company, notable for an FTC lawsuit over location data.

LG's connected-TV ad business, built on its 2018 purchase of Alphonso.

Mobile app advertising platform (with Vungle) that listed on Nasdaq in June 2026.

Microsoft's professional network, the default ad channel for business-to-business marketers.

Identity and data-collaboration company (RampID, clean rooms), agreed in 2026 to be bought by Publicis.

Data management and identity company acquired by Publicis in 2025.

Eye-tracking attention research company.

UK click-fraud prevention company (formerly PPC Protect) for paid search and social.

CTV-focused buying platform used by local broadcasters and agencies.

B2B account-based marketing platform using intent data to target companies.

India's largest independent media agency group, part of Madison World.

The largest independent sell-side platform, especially in connected TV.

Incrementality measurement platform for direct-to-consumer brands.

US body that audits and accredits ad measurement, including invalid-traffic detection.

Contextual ad company powering the Yahoo-Bing contextual network, with large teams in Mumbai.

Pioneering independent DSP that collapsed into bankruptcy in 2023 and was bought by Infillion.

The back-office software most big agencies use to plan, buy and pay for media, now with Flashtalking and Innovid.

Ad management company that runs ads for thousands of food, lifestyle and hobby blogs.

Retail media arm of MercadoLibre, Latin America's largest e-commerce and fintech company.

Owner of Facebook, Instagram, WhatsApp and Threads, and the second-largest digital ad seller worldwide.

Indian ad fraud detection and brand protection company for app and web advertisers.

Search ads on Bing and Copilot, plus ads across Microsoft properties, Xbox and partner sites.

Mobile ad network owned by Hong Kong-listed Mobvista, strong with game advertisers.

Self-serve connected-TV advertising platform for performance marketers; listed in 2025.

Attention and viewability measurement pioneer, bought by Oracle in 2017 and shut down in 2024.

Hong Kong-listed mobile ad tech group, parent of Mintegral.

Machine-learning mobile DSP for app marketers, also powering retail media for commerce platforms.

South Korea's dominant search portal, selling search, display and shopping ads.

The biggest streaming service, which added a cheaper ad-supported plan in 2022 and now runs its own ad tech.

US self-regulatory body for ad tech companies on data and privacy practices.

Video and CTV ad tech group (formerly Tremor International) with its own DSP, SSP and data.

The century-old TV ratings company, private since 2022 and agreeing to buy DoubleVerify in 2026.

Mobile advertising company built around personified, cookie-free targeting.

The largest ad holding company after absorbing Interpublic (IPG) in November 2025.

Fast-growing independent SSP and curation platform, with Italian roots.

Largest privacy and consent software company, powering many cookie banners.

Long-running independent SSP and exchange, focused on identity and sustainable supply.

Data collaboration platform for publishers, combining clean rooms and audience tools.

Content-recommendation pioneer that bought Teads in 2025 and took the Teads name.

US billboard and transit advertising company, including New York subway screens.

Software for brands managing ads across Amazon, Walmart, Instacart and other retail media networks.

Owner of CBS, Paramount+ and Pluto TV, formed by the 2025 Paramount–Skydance merger.

Pre-bid contextual and brand-safety data provider, which bought Adloox in 2026.

Israeli ad tech group combining search, CTV, DOOH (Hivestack) and retail media on one platform.

Publisher data platform that builds audiences on-device without third-party cookies.

Visual discovery platform where people plan purchases, selling shopping-focused ads.

Fraud and compliance analytics for CTV, apps and web, known for app and privacy risk ratings.

Independent out-of-home SSP, acquired by Broadsign in 2025.

Independent organisation that maintains Prebid, the open-source header-bidding software used across the web.

Israeli ad fraud detection company serving publishers, platforms and advertisers.

French agency group that became a leader by betting on data (Epsilon) and technology (Sapient).

Independent SSP running its own infrastructure, with large engineering operations in Pune, India.

Audience measurement pioneer turned AI-driven DSP for brands and agencies.

Japanese e-commerce, fintech and mobile group, owner of Rakuten Advertising and Rakuten Rewards.

Rakuten's global affiliate network, formerly LinkShare.

Creator-focused ad management company (formerly AdThrive and CafeMedia).

Community forum network selling ads targeted by topic and conversation, and licensing data to AI firms.

Smaller content-recommendation and native ad network.

TV operating system and streaming devices that make money selling ads on the home screen and in apps.

Polish retargeting and performance DSP using deep-learning models to bid.

Martin Sorrell's digital-only agency group, operating as Monks.

Salesforce's marketing suite for email, journeys and a customer data platform.

TV viewership data company using smart-TV ACR to measure and target ads.

Samsung's TV advertising business, selling ads on Samsung smart TVs and Samsung TV Plus.

Contextual advertising company using AI to place ads by content, not personal data.

Customer data platform owned by Twilio that collects and routes user data to marketing tools.

Native and video SSP that merged into Equativ in 2024.

Programmatic platform built for localised advertising, popular with local TV and radio sellers.

Marketing analytics and mobile attribution platform that joins cost and results data.

Satellite radio company that also owns Pandora and the AdsWizz audio ad-tech platform.

Former advertiser ad server that went bankrupt in 2019; its ad server and DSP went to Amazon.

Omnichannel marketing platform (formerly Kenshoo) for retail media, search and social.

Mobile in-app ad exchange owned by Verve Group.

Maker of Snapchat, selling ads between Stories, in Spotlight and through AR lenses.

Cloud data platform that has become a backbone for advertising data sharing and clean rooms.

Ad tech developer that built early header-bidding and now focuses on publisher and CTV tools.

Consent management platform for large publishers, acquired by Didomi in 2025.

Publisher-focused SSP and tools company serving independent and long-tail sites.

Japanese ad fraud detection company protecting search, display and affiliate campaigns.

The largest audio streaming service, selling audio, video and podcast ads to free listeners.

CTV ad server owned by Magnite, used by streaming platforms to manage ad decisioning.

Fast-growing self-serve DSP popular with mid-sized agencies for native, display, video and CTV.

Challenger agency group built by Mark Penn, combining digital agencies with its own marketing tech.

Germany's leading out-of-home advertising company, also owning t-online.

Customer-acquisition and search-arbitrage marketplace (RAMP) that buys traffic and monetises it with search ads.

The biggest content-recommendation network: the "you may also like" links under news articles.

Outstream video and content-recommendation company formed when Outbrain bought Teads and took its name.

Owner of WeChat and QQ, and one of the biggest ad sellers in China through its apps and games.

Digital safety platform that monitors websites and ads for malware, data leakage and privacy issues.

The largest independent demand-side platform, used by agencies to buy ads across the open internet and CTV.

Short-video giant whose ad business rivals Meta and YouTube for younger audiences.

Click-fraud and invalid-traffic protection for Google, Microsoft and app campaigns.

Credit bureau whose TruAudience marketing unit, built on Neustar, provides identity and measurement.

SSP known for programmatic native ads and branded placements inside TV shows.

Audio ad tech and measurement company (streaming and podcast ratings), owned by iHeartMedia.

Industry initiative fighting ad fraud, malware and piracy through certification programmes.

Measures whether people in the room are actually watching the TV.

Ads in the Uber and Uber Eats apps, in cars and on car-top screens.

Game-engine maker that is also a major mobile ad network after merging with ironSource in 2022.

Consent management platform (with Cookiebot) used by hundreds of thousands of websites.

Mobile-first ad tech group (Smaato, Verve) listed in Stockholm and Frankfurt.

Self-serve DSP focused on connected TV and household-level targeting; its ticker is literally DSP.

TV measurement and planning company offering an alternative currency to Nielsen.

Leading programmatic digital out-of-home platform, bought by T-Mobile in 2025.

US smart-TV maker whose ad and data platform was bought by Walmart in 2024.

In-app video ad pioneer, merged with Liftoff in 2021.

Walmart's retail media network, selling ads on Walmart.com, in stores and across the web.

Owner of HBO Max, CNN, TNT and Discovery, now agreed to be acquired by Paramount Skydance.

Global body for advertisers, behind the cross-media measurement and brand-safety initiatives.

One of the largest advertising holding companies, owner of WPP Media (formerly GroupM) and Ogilvy.

The social network formerly called Twitter, now part of the Musk group of companies via xAI and SpaceX.

The former AppNexus exchange, owned by Microsoft, which shut its DSP in 2026 and kept its sell-side tools.

Web pioneer, now private-equity owned, running news, finance and sports sites plus a DSP.

Demand-side platform from Yahoo, descended from AOL and BrightRoll ad tech.

Russia's largest search engine and ad platform, now a Russian-owned company listed in Moscow.

Mobile ad formats and attention-based optimisation marketplace.

Brand-suitability measurement for YouTube, TikTok, Meta and other social video.

Data-driven marketing cloud combining an identity graph, CDP, email and a DSP.