Who are the big 5 advertising agencies?
The "Big 5" advertising agency holding companies, the parent groups behind hundreds of individual agencies, are WPP (which owns Ogilvy, VMLY&R, GroupM), Omnicom (BBDO, TBWA, DDB), Publicis Groupe (Publicis Worldwide, Saatchi & Saatchi, Leo Burnett), Interpublic (McCann, MullenLowe, R/GA), and Dentsu. Together they represent the majority of global agency spending. Independent agencies fill a distinct market segment focused on flexibility and specialization.
Scale is rarer than the question suggests
The global holding companies sit above the US independent market that The Wall indexes, so they do not appear here. What the index adds is scale context. Of 374 US listings naming advertising, only 14 run 250 or more people while 311 run fewer than 50.
The most common team size in the group is 10 - 49. The advertising business most US buyers actually hire from is a few dozen people, not a few thousand.
Scale does not buy a cheaper hour either. 238 of the 312 US advertising firms that publish an hourly rate sit between $100 and $199, the same band the smallest shops occupy. What size buys is bench depth and coverage.
How to use this
If the pitch you need is a national campaign across many markets, the holding company networks are the right call. For anything smaller, their minimums will price you out before the work starts.
How this was computed. Every figure on this page is counted from The Wall's own directory of approved, US-headquartered, machine-verified-live listings: 3,460 of them in the snapshot captured 2026-09-14. Rates, minimum project sizes, team sizes, founding years and ratings are provider-declared figures published on public profiles. 1,738 of those listings publish a service list, and that field holds at most 4 services per firm, so service counts are counts of what firms name first rather than everything they sell. Percentages of disclosed values exclude listings that publish no figure. Nothing here is modeled or estimated. Sourcing standards: editorial policy.
Why this matters
Google puts this question in People Also Ask for the "marketing agency" query, which means buyers are asking it while they shop. The Wall answers it from the directory position: we index 3,460 verified US growth-services vendors across 10 pillars, so the figures above come from those records rather than from a survey.
If you are evaluating vendors in this category, the Marketing pillar page carries the full US firm list with rate, team size and headquarters filters.