[TL;DR: Byron Sharp's research across 130+ brands proves that brand growth comes overwhelmingly from reaching new buyers, not from deepening loyalty with existing ones. Most SMEs have their ad strategy backwards. Here's the data, and what to do about it.]

The Loyalty Trap: Why Your Best Customers Can't Grow Your Business

Most small business owners obsess over retention. Keep the customers you have. Get them to buy more often. Build loyalty programs. Reward the regulars. It sounds sensible. It feels responsible. And according to four decades of rigorous marketing science, it is almost completely wrong as a growth strategy.

Byron Sharp, Professor of Marketing Science at the Ehrenberg-Bass Institute, has spent his career doing something most marketing academics avoid: testing marketing assumptions against actual data. His book "How Brands Grow" draws on single-source consumer panel data across 130+ brands in 13+ product categories. What he found should change how every SME thinks about their advertising budget.

Growth comes from penetration. Not loyalty.

What the Data Actually Shows

Sharp and his colleagues analysed 880 award-winning advertising campaigns from the IPA (Institute of Practitioners in Advertising), looking at how the successful ones actually drove growth.

The results were stark. 82% of winners grew through penetration, meaning they reached more buyers who had never purchased or purchased rarely. Only 2% succeeded primarily through loyalty strategies.

That is not a marginal finding. That is a structural one.

And yet, if you listen to most marketing conversations in Australian small business circles, loyalty is the obsession. "We need to get our existing customers to spend more." "Our best customers are worth 10x a new one." "It costs five times more to acquire than retain."

That last claim is perhaps the most damaging. It circulates everywhere, gets cited in sales pitches, gets used to justify spending on loyalty programs and customer retention over reach campaigns. Sharp's research found no empirical support for it. None.

The Double Jeopardy Law

Sharp formalised a principle called the Double Jeopardy Law. It is one of the most consistently validated findings in marketing science, replicated across categories, countries, and decades.

Here is how it works. Brands with smaller market share suffer on two dimensions simultaneously: they have fewer buyers (first jeopardy), and those buyers purchase slightly less frequently (second jeopardy). Both penetration and loyalty decline together as a brand shrinks.

The important thing to notice is what does NOT change much as you move up the market share ladder: purchase frequency. Heavy users buy roughly the same amount whether they are loyal to a large brand or a small one. The penetration gap is enormous. The loyalty gap is tiny.

Sharp used data from the UK washing powder market to illustrate this. Persil had 22% market share, 41% penetration, and buyers purchased 3.9 times per year on average. A smaller competitor had 10% market share, 19% penetration, and 3.8 purchases per year. Penetration dropped by more than half. Purchase frequency barely moved.

This tells you something important. You cannot grow a brand primarily by squeezing more purchases out of existing customers. The ceiling is low and mathematically constrained. The growth is in the pool of people who currently do not buy from you at all, or barely do.

Light Buyers Are Your Growth Engine

Here is the part that surprises most business owners.

Roughly the top 20% of your buyers generate about 50% of your revenue. That feels like confirmation that you should focus on those people. Keep them happy. Build loyalty. They are valuable.

But Sharp's analysis shows that heavy buyers will naturally moderate their behaviour over time. This is called the Law of Buyer Moderation. Your most enthusiastic customers this year will buy slightly less next year. They regress toward the mean. You cannot stop this by sending them more emails or giving them a loyalty card.

Meanwhile, non-buyers and light buyers are the largest pool by definition. Encouraging a large group of infrequent buyers to make even one additional purchase across the year has more mathematical impact than pushing heavy users to buy more. There is simply more of them.

Sharp puts it directly: "30% of Coca-Cola buyers purchase less than once yearly; just 4% of buyers deliver nearly 25% of total sales." If Coke built its entire marketing strategy around nurturing that 4%, it would be capping its own growth.

For an SME in Adelaide, the equivalent is this. If you manage 80 active clients or customers, the biggest growth opportunity is not getting those 80 to pay more. It is reaching the thousands of potential buyers in your market who have never heard of you, or who vaguely know you exist but have never been prompted to act.

What This Means for Your Ad Budget

This is where the theory hits the spreadsheet.

Most SME advertising I see is over-indexed toward people who are already in the funnel. Retargeting campaigns that only show ads to website visitors. Email sequences that go to existing subscribers. Loyalty promotions for repeat customers. These are not useless, but they are talking to a small, self-selecting pool.

The research says the better investment is reach. Broad awareness campaigns that get your brand in front of people who are not yet thinking about buying. Byron Sharp calls this building mental availability: the likelihood that someone thinks of your brand when they enter the buying situation.

The practical translation for Google Ads is that brand campaigns and exact-match keyword strategies are mostly capturing demand that already exists for you. Valuable, but not the growth driver. Broader match, competitor terms, adjacent intent keywords, and display campaigns are building the surface area of who knows you exist. That is where the penetration opportunity lives.

For Facebook and Meta Ads, the implication is similar. Retargeting your existing audience feels efficient because conversion rates are higher on warm traffic. But the audience is small and eventually saturated. The growth comes from broad prospecting campaigns that reach the people who have never interacted with your business at all.

Sam Tomlinson, who writes extensively on advertising investment strategy, frames this as a capital allocation problem. Most businesses feed their safe, familiar channels while starving reach. The accounts that grow compound their investment into the channels producing the best risk-adjusted return on new customer acquisition, not just the channels that feel comfortable because they talk to people who already know you.

The Counterintuitive Implication for Retention

None of this means you should ignore existing customers. Retention matters, service quality matters, and a business that churns clients constantly is burning money. But the point is about proportion and priority.

If you are a growing SME and you are spending 80% of your marketing effort on retention and only 20% on reach, you have the ratio backwards relative to what the evidence says drives growth. Even if your retention campaigns are performing, you are leaving the larger opportunity untouched.

The loyalty programs that do work are often working for a different reason than marketers assume. They are not converting light buyers into heavy buyers. They are reducing churn among buyers who were already fairly loyal, which is useful but marginal. The research consistently shows that loyalty programs deliver small frequency improvements among heavy users who were already going to buy, while barely moving penetration at all.

Sharp measured this directly with Australian supermarket loyalty programs. Kmart's program predicted a penetration of 52%, actual result with the program was 48%. Coles predicted 64%, delivered 61%. The programs did not grow their customer base. They marginally deepened frequency among people who were already customers, while doing nothing for the much larger group of people who never shopped there.

Making It Practical

If you take one thing from Sharp's research, make it this: your next marketing dollar is probably better spent reaching someone who does not know you than rewarding someone who already buys from you.

That means:

• Prioritise reach campaigns in your Google Ads and Meta strategy, not just retargeting and warm audiences


• Invest in content and SEO that gets you in front of people entering the category for the first time


• Measure new customer acquisition rate as a primary metric, not just retention rate or repeat purchase rate


• When reviewing ad performance, ask not just "how did we do with existing buyers?" but "how many genuinely new buyers did we reach?"

Byron Sharp did not invent a new marketing theory. He tested the old ones against evidence and found most of them wanting. The loyalty myth is one of the most persistent and costly ones in small business marketing.

Growth lives outside your current customer base. That is where your advertising needs to go.

FAQ

Is customer retention really less important than acquiring new customers?

Retention is important for maintaining your current revenue base and managing churn, but it is rarely where growth comes from. Byron Sharp's analysis of over 880 IPA award-winning campaigns found that 82% achieved growth through penetration (reaching new buyers) and only 2% succeeded primarily through loyalty strategies. The practical implication is not to ignore existing customers, but to recognise that the proportional investment most SMEs put into retention versus acquisition is typically the wrong way around. If you are spending more on keeping existing customers happy than on reaching potential buyers who have never heard of you, you are capping your own growth.

Why do marketing agencies and consultants push loyalty programs so hard if the data says they do not drive growth?

Partly because loyalty programs are measurable and defensible. You can show that retained customers have higher lifetime value, that repeat buyers convert at higher rates, and that churn costs money. These are all true. The problem is that they measure within a closed system of existing customers, not the larger pool of potential buyers outside it. Loyalty also feels intuitive: it seems logical that deepening relationships with your best customers should be the priority. The Ehrenberg-Bass Institute's research suggests this intuition is wrong at scale, and that brands consistently overestimate how loyal their customers are and underestimate how important light and non-buyers are to their future growth.

How does this change how I should evaluate my Google Ads campaigns?

Most Google Ads setups for SMEs are heavily weighted toward bottom-of-funnel, high-intent, branded, and retargeting campaigns. These are efficient because they capture people who are already looking for you or who have already visited your site. But they are not generating reach. They are converting demand that already exists. If you want to apply Sharp's framework, you need to invest in campaigns that reach people who are in the category but have not yet heard of your business. That means broader match keywords, competitor terms, and display campaigns targeted at category-relevant audiences. Measure the proportion of genuinely new contacts coming into your system through paid channels each month. That number is a more honest indicator of whether your advertising is doing growth work or just conversion work.

What does "mental availability" mean and how do I build it for a small business?

Mental availability is Byron Sharp's term for the probability that your brand comes to mind when a buyer enters a buying situation. It is not general brand awareness. It is specifically whether people think of you at the moment they need what you provide. For an SME, mental availability is built by consistent, broad-reach advertising that links your brand to the relevant buying triggers. For a plumber in Adelaide, it is being the name that comes to mind when a pipe bursts. For a digital marketing agency, it is being thought of when a business owner decides they need help with Google Ads. You build it through reach over time, through SEO and content that surfaces when people are actively searching, and through consistent branding that makes you easy to recognise and recall. It is not built by sending promotional emails to people who are already your customers.