Your Loyal Customers Are Not Your Growth Engine. The Maths Proves It.

Most small business owners have heard the same advice so many times it feels like a law of nature: keep your existing customers happy and growth will follow. Invest in loyalty. Reward repeat buyers. The new ones will come eventually.

It sounds right. It feels right. And a massive body of empirical evidence says it is wrong.

A 2024 Bain & Company analysis of over 4,000 consumer brands found that penetration growth accounts for more than 70% of revenue growth. Not loyalty. Not upselling. Not retention programs. Just getting more people to buy from you in the first place.

That finding alone should change how every small business allocates its marketing budget. But the implications run deeper than most people realise, especially when you combine it with what we now know about timing, memory, and the 95% of your market that is not shopping today.

The loyalty figure that never had a source

"It costs five times more to acquire a new customer than to retain an existing one."

This claim appears in marketing textbooks, CRM vendor pitch decks, and roughly half the business articles published in any given week. Byron Sharp, Professor of Marketing Science at the Ehrenberg-Bass Institute, looked for the original data behind it. He could not find any. No peer-reviewed study. No replicable methodology. No dataset.

What he did find, across decades of research spanning 130+ brands in 13+ product categories, is that brands grow primarily through penetration, meaning the number of people who buy from them at least once, not through increased purchase frequency from existing buyers.

A February 2026 study from the same institute, published in the Journal of Business Research, examined this question specifically for tiny brands. The finding: even the smallest brands grow through penetration. When tiny brands manage to increase their market share, the gains come from reaching new buyers, not from squeezing more purchases out of the few loyal ones they already have.

The loyalty-first advice is not just imprecise. For a small business trying to grow, it points the budget in the wrong direction.

Double jeopardy: the tax small brands pay

The Ehrenberg-Bass Institute's most consistently validated finding is something called the Double Jeopardy Law. It works like this: brands with smaller market share have fewer buyers (obvious) and those buyers are also slightly less loyal (not obvious at all).

Here is what the data looks like in a typical consumer category:

The gap between big and small brands is almost entirely explained by how many people buy from them. Loyalty is roughly the same. If you are a small business trying to close that gap, loyalty programs and retention campaigns are working the wrong lever. The lever that moves is reach.

This pattern holds across B2B markets, financial services, automotive, and professional services. It is not a quirk of consumer packaged goods. It is one of the most replicated findings in marketing science.

The 95-5 problem: why most of your market is invisible to you

Here is where the research gets uncomfortable for anyone running a performance-only marketing strategy.

Professor John Dawes at Ehrenberg-Bass developed what the LinkedIn B2B Institute calls the 95-5 rule: at any given moment, roughly 95% of your potential buyers are not in the market. They are not searching. They are not comparing quotes. They are not clicking ads.

The maths is straightforward. If your average customer buys your type of service once every five years, then in any given quarter only about 5% of your total addressable market is actively looking. The other 95% will need you eventually, but right now they are going about their lives.

Google Search Ads catch the 5%. They are brilliant at it. When someone searches for your service, you want to be there. But if your entire budget goes to capturing active searchers, you are harvesting from a pool you did nothing to fill.

The brands that consistently win are the ones that build memory before the buying moment arrives. When that 95% eventually enters the market, they already have a shortlist in their head. If you are on it, you get considered. If you are not, you do not exist, no matter how good your Google Ads are.

This is the concept Sharp calls mental availability: the probability that your brand comes to mind when a buying situation arises. It is not awareness in the abstract "have you heard of us" sense. It is whether your name surfaces at the exact moment someone thinks, "I need to get that fixed."

Building mental availability requires reaching people who are not yet buying. That means broader campaigns on Facebook, Instagram, or YouTube. Content that reaches beyond your existing audience. The kind of spend that does not produce a neat cost-per-lead figure this month but steadily fills the pool of people who will search for you by name next year.

We explored this dynamic in more detail in Why 95% of Your Future Customers Aren't Googling You Right Now.

What the effectiveness data actually says

Les Binet and Peter Field have spent years analysing the IPA Effectiveness Databank, the most rigorous collection of proven advertising case studies in the world. Their analysis of 880+ campaigns found that campaigns aiming to increase penetration have dramatically higher success rates than campaigns aiming to increase loyalty.

Their recommended budget split for most categories: roughly 60% toward brand building (broad reach, emotion-led, memory-creating) and 40% toward activation (direct response, conversion-focused, sales-driving).

But here is the problem. Between 2019 and 2024, the market inverted this ratio, allocating 68.8% to performance and just 31.2% to brand. The result? Long-term effectiveness declined across the board while customer acquisition costs climbed. DTC brands saw acquisition costs inflate 30-70% compared to two years prior. Meta CPMs rose roughly 20% year-on-year through 2025.

The businesses paying more and more for each new customer are, in many cases, the ones that stopped investing in the broader brand work that makes acquisition cheaper over time. They are harvesting without planting.

The light buyers you are probably ignoring

One more counterintuitive finding. Ehrenberg-Bass research shows that light buyers make up 70-80% of any brand's customer base. These are the people who bought once, or who buy occasionally. Most businesses ignore them in favour of the heavy buyers, the top 20% who seem to drive everything.

But the old 80/20 rule overstates the case. The real ratio is closer to 50/20: the top 20% of customers generate about half of purchases, not 80%. The other half comes from the vast pool of light and occasional buyers.

And heavy buyers naturally moderate over time. They regress toward the mean. The customer who called you five times this year might call you twice next year regardless of what you do.

Getting a large group of light buyers to make one additional purchase is, mathematically, a bigger growth opportunity than any retention campaign aimed at your best customers. And reaching new people who have never bought from you is how you build that light buyer pool in the first place.

What this means for your marketing budget

If you run a small business and you are weighing customer acquisition vs retention, here is what the evidence points to.

The uncomfortable conclusion

Your best customers are your best customers right now. Your growth is sitting with the people who have never heard of you, or who heard of you once and forgot, or who vaguely know you exist but have no reason to call today.

Marketing to those people feels less certain. The return comes later. The attribution is messier. That ambiguity is exactly why most businesses avoid it, and exactly why the ones that lean into it tend to grow faster.

The data across 4,000+ brands, 880+ effectiveness case studies, and six decades of marketing science research all point in the same direction. Reach more people. Build memory. Be easy to find when they are ready. That is how businesses grow.

Further Reading

• The Biggest Contributor to Brand Growth - Bain & Company's analysis of penetration as the primary growth driver across 4,000+ brands
• Tiny Brands, Big Challenges - 2026 Ehrenberg-Bass study on how even the smallest brands grow through penetration
• The 95-5 Rule - LinkedIn B2B Institute and Ehrenberg-Bass research on why most buyers are not in market
• The Brand-Performance Balance - Applying Binet & Field's 60/40 framework to modern marketing
• Light Buyers: Why They Grow the Brand - 2026 synthesis of Ehrenberg-Bass light buyer research