Inside Costco’s Secretive Retail Media Strategy: What Mark Williamson Revealed

Costco has always been the effortlessly cool kid of the retail media world: unbothered by hype, quietly confident, and doing things entirely on its own terms. In this episode, I unpack what makes Costco’s retail media approach so different from the 80+ U.S. retail media networks vying for attention, and why their “member-first, margin-second” philosophy is more than just a tagline.After digging through Mark Williamson (Retail Media AVP at Costco) interviews, I piece together a clearer picture of how Costco is building a retail media business that deeply aligns with its culture, elevates member value, and defies the standard playbook. I explore their unique team structure and ruthlessly disciplined data foundation, as well as the philosophical stance that guides every media decision they make.This episode is sponsored by Mirakl AdsTimeline[00:19] – Why Costco avoids the splashy retail media hype and plays the long game[02:53] – Mark Williamson explains why “monetization” isn’t even in Costco’s vocabulary[04:47] – The uncompromising member-first philosophy and how it blocks “free money”[07:15] – How Costco’s Growth Management Team bridges merchants and media[09:00] – Why retail media revenue is immediately reinvested into merchandising[10:10] – The power of 100% member-identified transactions and deterministic dataLinks & ResourcesThis episode expanded on my recent article for The Drum - Costco: the retail media network that refuses to promote itselfThe Commerce Collective full episode with Mark Williamson - Putting Members First: How Value Guides Costco’s Retail Media VisionThe CPG Guys full episode with Mark Williamson - Media that Drives Retail Sales with Costco’s Mark WilliamsonFollow Mark Williamson, Retail Media AVP at Costco, on LinkedInRead my articles:The ‘How Brands Grow’ Dogma Wants To Have A Word With Retail MediaHow Can RMNs Tap Upper-Funnel Brand BudgetsI'll be diving into the findings of the Pentaleap H2 2025 Sponsored Products Benchmark report with Pentaleap co-founder and CEO Andreas Reiffen on Thursday December 4 at 11AM ET! Join us LIVE here Are you based in Atlanta or plan to be in the ATL area on Weds Dec 3rd? Join me and a couple dozen of your new retail media industry besties for a festive happy hour! Register hereSubscribe to Retail Media Breakfast Club's daily newsletterFollow Kiri on LinkedIn