Company lists · Data refreshed September 2026

Top 25 Online marketplace advertising agencies worldwide

RevenueBase identified 7,000 online marketplace advertising agencies worldwide as of September 2026 and tracks 76,771 professional contacts across them, including 17,438 with verified work emails. The United States is the largest market and London the largest hub.

This list covers online marketplace advertising agencies worldwide, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 29, 2026. Country and city lists for online marketplace advertising agencies follow the table.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 29, 2026 86% judged on-target in blind review
7,000Companies
76,771Contacts tracked
17,438Verified emails
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The 25 largest online marketplace advertising agencies worldwide

Ranked by team size
Top 25 of 7,000 online marketplace advertising agencies worldwide, ranked by team size, largest first. Data refreshed Sep 29, 2026. RevenueBase Smart Search rates how each company's information relates to online marketplace advertising agencies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceVentura, CA, United StatesHQ checked Sep 29, 20261,001-5,0004,307 contacts →

Indirect evidence

“It's more than just clicks.”

Source: RevenueBase Database · checked Sep 29, 2026
2Partial evidenceAmsterdam, NetherlandsHQ checked Sep 29, 20261,001-5,0003,553 contacts →

Partial evidence

“At OLX, we build leading AI-first marketplace ecosystems, powered by trust and loved by customers.”

Source: RevenueBase Database · checked Sep 29, 2026
3Partial evidenceAmsterdam, FranceHQ checked Sep 29, 20265,001-10,0001,134 contacts →

Partial evidence

“Adevinta is a leading online classifieds group and champion for sustainable commerce across Europe and beyond.”

Source: RevenueBase Database · checked Sep 29, 2026
4Strong evidenceFoster City, CA, United StatesHQ checked Sep 29, 2026501-1,0001,035 contacts →

Strong evidence

“Powering Performance Marketplaces In Digital Media QuinStreet is a pioneer in powering decentralized online marketplaces that match searchers and “research and compare” consumers…”

Source: RevenueBase Database · checked Sep 29, 2026
5Partial evidenceUnited StatesHQ checked Sep 29, 2026501-1,000910 contacts →

Partial evidence

“We’re Magnite (NASDAQ: MGNI), the world’s largest independent sell-side advertising company.”

Source: RevenueBase Database · checked Sep 29, 2026
6Indirect evidenceCopenhagen, DenmarkHQ checked Sep 29, 2026501-1,000847 contacts →

Indirect evidence

“Adform is the most powerful and safe media buying platform in the world.”

Source: RevenueBase Database · checked Sep 29, 2026
7Strong evidenceSan Jose, CA, United StatesHQ checked Sep 29, 202610001+744 contacts →

Strong evidence

“eBay is one of the world’s largest online marketplaces, connecting people with the things they need and love virtually anytime, anywhere.”

Source: RevenueBase Database · checked Sep 29, 2026
8Strong evidenceZurich, SwitzerlandHQ checked Sep 29, 2026501-1,000543 contacts →

Strong evidence

“Welcome to SMG Swiss Marketplace Group We are a pioneering network of online marketplaces and a cutting-edge digital company that simplifies people’s lives with innovative…”

Source: RevenueBase Database · checked Sep 29, 2026
9Partial evidenceDubai, United Arab EmiratesHQ checked Sep 29, 2026201-500512 contacts →

Partial evidence

“dubizzle is the UAE'S favorite marketplace to buy, sell and find anything.”

Source: RevenueBase Database · checked Sep 29, 2026
10Indirect evidenceNew York, NY, United StatesHQ checked Sep 29, 2026201-500468 contacts →

Indirect evidence

“Quartile, the world's largest retail media optimization platform, is a trusted partner for multichannel e-commerce success.”

Source: RevenueBase Database · checked Sep 29, 2026
11Partial evidenceBerlin, GermanyHQ checked Sep 29, 2026201-500462 contacts →

Partial evidence

“Kleinanzeigen is a free online classifieds market that brings the joy of sustainable trade to everyone.”

Source: RevenueBase Database · checked Sep 29, 2026
12Indirect evidenceUnited StatesHQ checked Sep 29, 2026201-500400 contacts →

Indirect evidence

“Internet Marketing and Product Brokerage”

Source: RevenueBase Database · checked Sep 29, 2026
13Indirect evidenceCoral Gables, FL, United StatesHQ checked Sep 29, 2026n/a394 contacts →

Indirect evidence

“E-commerce - Construye una Marca - Digital Marketing”

Source: RevenueBase Database · checked Sep 29, 2026
14Partial evidenceJakarta Selatan, IndonesiaHQ checked Sep 29, 20261,001-5,000388 contacts →

Partial evidence

“OLX, as a subsidiary of Astra Group is the largest online classifieds site in Indonesia, plays a pivotal role in connecting sellers and buyers across a diverse spectrum of…”

Source: RevenueBase Database · checked Sep 29, 2026
15Strong evidenceBuffalo, NY, United StatesHQ checked Sep 29, 2026501-1,000383 contacts →

Strong evidence

“LocalEdge, a Hearst Media Services Company, offers a full suite of online advertising products and services for any size business and budget across the country.”

Source: RevenueBase Database · checked Sep 29, 2026
16Indirect evidenceMilan, ItalyHQ checked Sep 29, 2026201-500344 contacts →

Indirect evidence

“Subito è l'azienda n.”

Source: RevenueBase Database · checked Sep 29, 2026
17Indirect evidenceOslo, NorwayHQ checked Sep 29, 2026201-500335 contacts →

Indirect evidence

“Nesten alle i Norge prøvd FINN.no Hvert år tilbringer hver nordmann i snitt 30 timer på tjenesten vår, og til sammen surfer brukerne våre gjennom mer enn 15 milliarder sider.”

Source: RevenueBase Database · checked Sep 29, 2026
18Partial evidenceUtrecht, NetherlandsHQ checked Sep 29, 2026201-500272 contacts →

Partial evidence

“Channable is the Multichannel Platform that empowers eCommerce businesses to quickly and reliably grow on any online channel, achieving quicker time to market, improved…”

Source: RevenueBase Database · checked Sep 29, 2026
19Indirect evidenceColombo, Sri LankaHQ checked Sep 29, 2026201-500271 contacts →

Indirect evidence

“ikman (ඉක්මන්) is derived from the sinhala word "fast" or "quick" and is our signature style of offering exceptional buying/ selling experience to our consumers.”

Source: RevenueBase Database · checked Sep 29, 2026
20Indirect evidenceWien, AustriaHQ checked Sep 29, 2026201-500266 contacts →

Indirect evidence

“The willhaben dream team For us, a great workplace means much more than a nice office or a few attractive benefits - even though we have a lot to offer in that regard.”

Source: RevenueBase Database · checked Sep 29, 2026
21Indirect evidenceLimassol, CyprusHQ checked Sep 29, 2026201-500265 contacts →

Indirect evidence

“Founded in 2013, Adsterra is now a global ad network with a unique Partner Care approach, trusted by 50K+ advertisers and publishers worldwide.”

Source: RevenueBase Database · checked Sep 29, 2026
22Indirect evidenceMarkham, ON, CanadaHQ checked Sep 29, 202651-200252 contacts →

Indirect evidence

“Canada’s #1 leader in the Digital Marketing industry.”

Source: RevenueBase Database · checked Sep 29, 2026
23Partial evidenceKuala Lumpur, MalaysiaHQ checked Sep 29, 202651-200248 contacts →

Partial evidence

“Mudah.my is Malaysia’s leading marketplace that offers a free and convenient platform for people to buy and sell new and preloved goods just with a simple post of an ad.”

Source: RevenueBase Database · checked Sep 29, 2026
24Strong evidenceJeddah, Saudi ArabiaHQ checked Sep 29, 2026501-1,000248 contacts →

Strong evidence

“Where innovation & simplicity fuse to bring effective offline/online advertising solutions that propel our partners closer to their marketing goals.”

Source: RevenueBase Database · checked Sep 29, 2026
25Indirect evidenceLos Angeles, CA, United StatesHQ checked Sep 29, 2026201-500242 contacts →

Indirect evidence

“AdMedia helps Agencies and Brands meet their KPIs and hit their ROI objectives.”

Source: RevenueBase Database · checked Sep 29, 2026

Showing 25 of 7,000 online marketplace advertising agencies worldwide

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Online marketplace advertising agencies worldwide at a glance

As of Sep 29, 2026
22.7%Verified-email coverage
11.0Average contacts per company
1-10Median size (employees)
2.0%Largest-city concentration · London
Sep 29, 2026Page data refreshed

Companies by employee count

1-10
4,198
11-50
2,056
51-200
497
201-500
142
501-1,000
38
1,001-5,000
13
5,001-10,000
11
10001+
25

Email recency is reported on each country list linked below.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among online marketplace advertising agencies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
Coverage
Every country. Country and city lists for online marketplace advertising agencies are linked below.
What qualifies
Companies worldwide whose own description of what they do matches “online marketplace advertising agencies”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names online marketplace advertising agencies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among online marketplace advertising agencies, and records with no verified work email.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 17,438 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 29, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Online marketplace advertising agencies by location

40 lists · largest first

Every Online marketplace advertising agencies list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Cities

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names online marketplace advertising agencies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many online marketplace advertising agencies are there worldwide?

RevenueBase identified 7,000 online marketplace advertising agencies worldwide as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

The Trade Desk, headquartered in Ventura, tops this list with the largest team on record.

Which country has the most online marketplace advertising agencies?

The United States leads with 1,099 companies, followed by India (645) and the United Kingdom (286). Every online marketplace advertising agencies list by country and city is linked on this page.

Which city has the most online marketplace advertising agencies?

London leads with 142 headquartered companies, followed by New York (86) and Sao Paulo (64).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 17,438 verified decision-maker contacts tracked across these 7,000 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 29, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.