Buyers Are Polygamously Loyal to Brands: The Data Behind the Myth of Exclusive Loyalty

By German Tirado, August 13, 2025

Introduction

For decades, marketing teams have built strategies on the comforting belief that once a customer chooses a brand, they form an emotional bond that locks in repeat purchases for years to come. This story fuels the idea that customer loyalty is exclusive, unshakable, and the ultimate goal of brand building. The assumption is that loyal customers will keep returning, unaffected by competitors’ offers, marketing campaigns, or distribution advantages.

But this picture of exclusive brand loyalty is a myth — and one that’s costing brands growth opportunities. Decades of empirical evidence from the Ehrenberg-Bass Institute for Marketing Science show that buyers — whether they are everyday consumers or high-value B2B decision-makers — are polygamously loyal. In other words, customers have a portfolio of brands they buy from, often switching between them depending on the buying situation, availability, price, or even habit.

This behavior is not limited to fast-moving consumer goods like coffee, snacks, or cleaning supplies. In B2B markets, even long-term clients who appear “loyal” still evaluate alternative suppliers when contracts are up for renewal, when new needs arise, or when new players capture their attention through advertising. A satisfied IT services customer today may also be a trial client for another provider next year — not because they were unhappy, but because they naturally buy from multiple brands over time.

Understanding this reality is crucial because it reframes what customer loyalty really means. Loyalty is rarely exclusive; it’s a statistical pattern governed by laws of buying behavior like the Double Jeopardy Law, the 95–5 Rule, and the concept of Category Entry Points (CEPs). Instead of chasing an impossible goal of locking in customers forever, smart marketers focus on increasing mental and physical availability — making their brand one of the few that come to mind in a wide range of buying situations, and ensuring it’s easy to buy when needed.

In this article, we’ll dismantle the myth of exclusive brand loyalty using marketing science data, explain why polygamous loyalty is the norm across categories, and show you how to grow your brand by winning more buying moments — even from your competitors’ most “loyal” customers.

Introduction
The Evidence for Polygamous Loyalty
Why Exclusive Loyalty Is a Myth
The Role of Mental and Physical Availability
Action Plan for Marketers
Example: How This Works in Practice
Conclusion
Frequently Asked Questions (FAQs)
Works Cited

The Evidence for Polygamous Loyalty

The Ehrenberg-Bass Institute’s research across hundreds of categories confirms several replicated laws of buyer behavior that destroy the myth of unshakable brand allegiance.

1. The Double Jeopardy Law

Smaller brands not only have fewer customers but those customers also buy them less often than customers of larger brands [1]. This is a statistical pattern, not a judgment of quality. Larger brands have more penetration and slightly higher loyalty, while smaller brands face both disadvantages simultaneously.

2. Polygamous Loyalty Patterns

Even “loyal” buyers purchase from multiple brands. In many categories, customers regularly buy from 2–5 brands over a given period [2]. This applies to impulse goods like snack foods, habitual purchases like coffee, and considered B2B decisions like IT service providers.

3. Category Entry Points (CEPs)

When a buyer enters a category, they recall a shortlist of brands linked to specific buying situations — these are Category Entry Points [3]. For example:

“When upgrading to new software”

“When replacing an unreliable supplier”

“When needing overnight delivery”

Multiple brands may be linked to the same CEP in a buyer’s memory. Your goal is to be one of those brands, not the only one.

4. The 95–5 Rule

In B2B, up to 95% of category buyers are out-of-market at any given time [4]. They’re not ready to buy today, but they will buy in the future. The brands that come to mind when they finally enter the market are the ones that have maintained strong mental availability.

Why Exclusive Loyalty Is a Myth

Shared Customers Are the Norm

Most of your customers are also your competitors’ customers. Even the most “loyal” segment splits its purchasing across brands.

Switching Doesn’t Require Dissatisfaction

A buyer can be satisfied yet still choose another brand if it’s more visible, more accessible, or fits a specific need in that moment [2][3].

Memory Networks Are Crowded

Buyers recall several brands at the moment of need. Winning requires getting onto their mental shortlist and staying there through repeated exposure [3].

In B2B, long contracts may give the illusion of exclusivity, but at renewal time — or when new needs arise — buyers often invite multiple suppliers to compete.

The Role of Mental and Physical Availability

In a polygamously loyal world, mental and physical availability are your growth engines.

Mental Availability: Being easily thought of in buying situations. This is achieved by linking your brand to multiple Category Entry Points (CEPs) such as timing, location, activities, and emotional states [3].

Physical Availability: Making your brand easy to buy — broad distribution, accessible channels, competitive pricing, and minimal friction in the buying process [1].

Without mental availability, physical availability can’t convert. Without physical availability, mental availability can’t be acted upon.

Action Plan for Marketers

Accept the Truth About Loyalty
Stop chasing the fantasy of total exclusivity. Plan for overlap with competitors.
Target the Whole Market
Reach all category buyers, not just your existing customers or heavy buyers. Light buyers are crucial for long-term growth [1].
Build Broad CEP Coverage
Identify the When, Where, While, With, For Whom, How Feeling, and Why situations in which buyers consider your category. Link your brand to these cues through consistent marketing [3].
Invest in Broad Reach
Reach the 95% of out-of-market buyers so they’ll think of you when they become active buyers [4].
Refresh Memory Links Over Time
Memory decays. Competing brands fight to replace you in the buyer’s mind. Regularly refresh CEP associations.
Track the Right Metrics

Measure:

Penetration: % of category buyers who buy your brand annually

Mental Market Share: Share of buying situations where your brand is recalled

Average CEP Links per Buyer

Share of Category Buyers Reached per Quarter

Example: How This Works in Practice

Consider a mid-sized B2B software provider:

Without CEP strategy: Marketing focuses only on “when replacing outdated software.” This limits mental availability to a narrow set of buyers.

With CEP strategy: Marketing also builds associations with “when expanding a team,” “when opening a new office,” and “when needing remote access.” Now the brand appears in more buying situations, increasing share of mind and sales opportunities.

Over time, the brand is thought of in multiple contexts, giving it more chances to be chosen — even by buyers who also purchase from competitors.

Conclusion

The enduring belief that customers form exclusive, unshakable brand loyalty has been disproven time and again by decades of marketing science. From packaged goods to professional services, from retail to B2B procurement, the data reveals a consistent pattern: buyers are polygamously loyal. They maintain repertoires of multiple brands and choose among them depending on the buying situation, product availability, price, or even convenience.

This reality is not a weakness in your market — it’s a structural truth of customer buying behavior. Even the most “loyal” clients will share their spend across different brands. In B2B markets, long-term contracts, preferred supplier agreements, and strong relationships don’t erase the fact that competitors are always in the consideration set when renewal or replacement decisions are made.

For marketers, this means the growth opportunity lies not in trying to “lock in” customers forever, but in ensuring your brand is easy to think of and easy to buy. That’s the essence of mental availability and physical availability — the twin pillars of brand growth identified in How Brands Grow [1][2]. Your job is to build and refresh mental links to as many relevant Category Entry Points as possible (e.g., when urgent repairs are needed, when upgrading systems, when starting a new project), and to back that mental presence with distribution, accessibility, and frictionless purchasing.

By accepting the reality of polygamous loyalty, you free your strategy from chasing unattainable exclusivity and focus instead on expanding category penetration, growing mental market share, and increasing the frequency with which you’re chosen across diverse buying situations. That means:

Reaching all category buyers, including the 95% who are currently out-of-market [4].

Consistently refreshing Category Entry Point associations so your brand is remembered when it matters.

Making your products and services physically available across all the channels, locations, and formats your buyers prefer.

In the end, brands grow not by deepening loyalty among a small base, but by widening their customer base and winning more sales moments over time. When you embrace B2B marketing science and align your activities to the proven laws of buying behavior, you position your brand to thrive in a competitive, polygamously loyal marketplace — one in which your competitors’ customers can become yours, and yours can remain part of their repertoire for years to come.

Frequently Asked Questions (FAQs)

1. What does “polygamous loyalty” mean in marketing?

Polygamous loyalty refers to the consistent pattern where buyers purchase from multiple brands over time, even if they have a favorite. Instead of exclusive loyalty to one brand, customers maintain a repertoire of brands they choose from based on availability, price, occasion, or need [1][2].

2. How is polygamous loyalty different from brand switching?

Brand switching suggests a customer abandons one brand for another. Polygamous loyalty means customers regularly buy from several brands in the same category. Switching is normal and doesn’t require dissatisfaction — it’s a natural part of customer buying behavior.

3. Why is the myth of exclusive brand loyalty harmful for marketers?

Believing in exclusive loyalty can lead marketers to overinvest in retention strategies and ignore the biggest growth driver — reaching new and light buyers. This limits category penetration and reduces the number of Category Entry Points linked to your brand.

4. Does polygamous loyalty apply to B2B markets?

Yes. Even in B2B, where relationships and contracts can last years, buyers often evaluate multiple suppliers when contracts expire or new needs arise. The principles of mental availability and physical availability still determine whether you stay in the consideration set [3][4].

5. How can a brand grow in a polygamously loyal market?

Brands grow by:

Expanding mental availability through broad-reach advertising.

Linking the brand to multiple Category Entry Points.

Ensuring physical availability across channels and buying formats.

Reaching both heavy and light buyers consistently [1][3].

6. What role does mental availability play in polygamous loyalty?

Mental availability ensures your brand is easy to recall in buying situations. Since buyers consider multiple brands, the more CEPs your brand is linked to, the greater your chances of being chosen at the moment of need [3].

7. Can loyalty programs overcome polygamous loyalty?

Loyalty programs may slightly increase repeat purchase frequency among existing customers, but they don’t change the overall pattern. Customers will still buy from multiple brands, so focusing only on loyalty programs will not drive substantial growth [2].

8. What is the Double Jeopardy Law and how does it relate to loyalty?

The Double Jeopardy Law states that smaller brands suffer from both fewer customers and slightly lower purchase frequency compared to larger brands. This pattern holds across categories and explains why chasing exclusive loyalty is ineffective for growth [1].

9. How many brands do customers usually buy in a category?

In most categories, customers regularly purchase from 2–5 brands over a set period. This range can vary by category frequency, but exclusive loyalty to a single brand is rare [2].

10. What should marketers measure instead of loyalty rate?

Instead of focusing on loyalty percentages, track:

Category penetration

Mental market share

Average number of CEPs linked to your brand

Share of category buyers reached each quarter

Works cited

[1] Sharp, Byron. How Brands Grow: What Marketers Don’t Know. Oxford University Press, 2010.

[2] Romaniuk, Jenni, and Byron Sharp. How Brands Grow Part 2: Emerging Markets, Services, Durables, New and Luxury Brands. Oxford University Press, 2016.

[3] Romaniuk, Jenni. Category Entry Points in a Business-to-Business (B2B) World. Ehrenberg-Bass Institute for Marketing Science, 2022.

[4] Dawes, John. Advertising Effectiveness and the 95–5 Rule: Most B2B Buyers Are Not in the Market Right Now. Ehrenberg-Bass Institute for Marketing Science, 2021.