There's an appealing pitch that a certain type of agency makes: "We specialize exclusively in your industry. We know the buyers, we know the keywords, we know the market inside and out." It sounds like a competitive advantage. In reality, it might be the reason you're stuck.
When a digital marketing agency serves five, ten, or fifteen brands in the same product category, a fundamental conflict of interest emerges. Not a theoretical one. A structural one that directly impacts your revenue, your advertising efficiency, and your ability to grow into new channels.
Let's talk about why.
The Zero-Sum Problem
Digital marketing is not an unlimited resource. There are a finite number of keywords, a finite number of top search positions, a finite number of eyeballs on a category page on Amazon, and a finite number of shelf slots at Costco or Target.
When your agency also represents your direct competitor, someone has to lose.
Karl Sakas, an agency management consultant, puts it bluntly: "When only one client can 'win' in an industry, you can't ethically provide services to other clients in the same market." He calls it the "zero-sum game" problem, and it's unavoidable in performance marketing.
Consider a real scenario. You're a coffee roaster. Your agency also works with four other coffee roasters. Your Sponsored Products campaign on Amazon is targeting "organic whole bean coffee." So is your competitor's, managed by the same team, possibly the same account manager. Who gets the aggressive bid strategy? Who gets the conservative one? Who gets told "the market is just competitive right now" when their ACoS creeps up?
The answer is usually whoever spends more. And that means the agency's incentive is misaligned with yours from day one.
The Amazon Problem Gets Worse
On Amazon specifically, this conflict is devastating. Here's why:
Advertising is a direct auction against your competitors. If your agency runs PPC for two brands in the same sub-category, they are literally bidding against themselves. One client's cost-per-click goes up because the other client is in the same auction. The agency profits either way; you pay more for the same position.
Best Seller Rank is a zero-sum game. If your agency helps Brand A reach #1 in "Coffee Roasters" on Amazon, Brand B (also their client) necessarily drops. No agency is going to cannibalize their biggest revenue account to help their smaller one climb. They'll let both stagnate in the middle, collecting retainers from each.
Category intelligence becomes a liability. Your product roadmap, your pricing strategy, your upcoming promotions: the agency knows all of it. They also know your competitor's. A study from Harvard Business School by Alvin J. Silk examined exactly this dynamic, documenting how agencies serving competing clients face impossible decisions around confidential strategy and resource allocation.
As one agency founder admitted publicly after a client forwarded them a competitor's campaign brief from the same agency: "Same keyword strategy. Near-identical audience segmentation. The agency hadn't broken any law; they'd just reused what worked."
That's not a service. That's a template.
The Multi-Channel Ceiling
The conflict doesn't stop at Amazon. When a brand is ready to expand into Shopify DTC, into retail distribution with Costco or Target, or into TikTok Shop, they need an agency that's genuinely invested in finding those opportunities.
But if your agency works with five coffee brands and one of them already has the Costco relationship, are they going to introduce you to that same buyer? Are they going to pitch you for the same shelf? Of course not. They'll protect the existing relationship, even if your product is better, your margins are tighter, or your brand story resonates more with that retailer's demographic.
You don't just lose on Amazon. You lose on every channel your agency could have opened for you but didn't, because opening it would hurt another client.
The Case for Sector Expertise (And Its Limits)
To be fair, there are real advantages to working with an agency that knows your sector. They understand your buyer. They've seen what works. Their onboarding is faster because they already have the frameworks, the benchmarks, and the creative conventions.
An agency like PDG Media, which works exclusively in the coffee sector, openly lists clients including roasters, equipment brands, packaging companies, and RTD manufacturers. Their expertise is legitimate. Their testimonials confirm it.
That's real value. But here's the question every brand should ask: At what cost does that expertise come?
If you're a coffee roaster and your agency also works with three other coffee roasters, you're paying for expertise that's simultaneously being used to compete against you. Your market research informs their strategy for your rival. Your winning ad creative becomes a template for the next client. Your audience segments get repackaged.
You might get a faster start. But you'll hit a ceiling, because your agency can never fully commit to your dominance in the category. Your success is limited by their other obligations.
What We Do Differently at David Ricardo
At David Ricardo, we made a decision early on: one client per sub-category. No exceptions.
If we work with a coffee roaster, we will not take on another coffee roaster. Period. If a potential client approaches us and we already service a brand in that sub-category, we decline the business.
This isn't charity. It's strategy.
When we only serve one brand in a sub-category, our incentives are perfectly aligned with theirs. We want them to dominate. We want them to be #1 on Amazon, to win the Costco pitch, to crush it on Shopify, to own their TikTok Shop category. There's no internal conflict pulling us in another direction.
This structure lets us do things that conflicted agencies simply cannot:
We learn the full catalog. We're not skimming the surface across five competitors. We're deep in one brand's product line, understanding which SKUs have margin, which ones are rising, which ones should be bundled or discontinued.
We find cross-channel opportunities. When we see our client's Amazon sales surge, we can proactively recommend a Shopify expansion or a retail introduction without worrying about stepping on another client's territory.
We invest in operations. Because we're not spreading our attention across competing brands, we can understand our client's supply chain, their inventory cycles, their seasonal patterns. That operational depth translates into smarter advertising timing, better listing optimization, and more profitable promotions.
We protect confidentiality completely. Your pricing strategy, your keyword data, your product pipeline: none of it is at risk of informing a competitor's campaigns, because that competitor isn't in our portfolio.
The Running vs. Walking Analogy
Here's the simplest way to think about it: if you're a coffee roaster and you want to dominate the U.S. market, you want to run as fast as possible. You want your competitors reacting to what you're doing, not the other way around.
But if you're using the same agency as your competitors, you're not running. You're walking. Everyone moves at the same pace because the agency has no incentive to break the equilibrium. A stagnant middle is the most profitable outcome for them: all clients stay, none grow enough to question the arrangement, retainers keep flowing.
An exclusive agency partnership means there's no governor on your speed. Your agency wins when you win. Your growth is their growth. That alignment creates urgency, creativity, and commitment that a conflicted agency structurally cannot provide.
Questions to Ask Your Current Agency
Before your next contract renewal, ask these questions:
- How many brands in my sub-category do you currently serve?
- Do you run advertising for any of my direct competitors on the same platform?
- If I asked you to help me become #1 in my category on Amazon, which of your other clients would that displace?
- What's your policy on introducing clients to retail buyers if another client already holds that relationship?
- If a competitor approached you tomorrow, would you take them on?
If the answers make you uncomfortable, they should.
The Bottom Line
Sector expertise is valuable. But expertise without exclusivity is a trap. You're paying for knowledge that's being used both for and against you. You're funding an agency that profits from your competition's success as much as yours.
At David Ricardo, we believe your agency should be your unfair advantage, not a shared resource. One client per sub-category means your success is the only outcome we're optimizing for. No hedging, no conflicts, no ceiling.
If you want to walk, use the same agency as everyone else. If you want to run, find a partner that only runs with you.
Sources & References:
- Karl Sakas, "How to handle conflicts between competing clients" (sakasandcompany.com)
- Harvard Business School, Alvin J. Silk, "Conflict Policy and Advertising Agency-Client Relations"
- DMC Digital, "Can Your Agency Truly Serve You and Your Competitor?"
- SEO Hermit, "Is Your SEO Company Working for the Competition?"
- WAIM Hub, "What is a one-client-per-industry marketing agency?"
- PDG Media (pdgmediaagency.com/our-work) - coffee industry client portfolio
David Ricardo is a multi-channel e-commerce agency specializing in advertising, marketing, and operations for brands selling online. We work across Amazon, Shopify, TikTok Shop, and retail, with a strict one-client-per-sub-category policy.