For years, marketing has operated with a relatively stable definition of value: the best customers are the most loyal ones. They buy more often, spend more consistently, and are easier to identify and reach. In a world increasingly shaped by first-party data and retention metrics, that logic has only strengthened.
But it is also incomplete.
The next phase of growth is less about reinforcing behavior that already exists and more about identifying behavior that can still be influenced. The most valuable audience is not always the one most committed to your brand. It is the one most likely to change its mind.
The Limits of Loyalty-Led Growth
Modern marketing has become highly effective at identifying and engaging loyal customers. They represent a brand’s most reliable source of revenue, with established preference, higher purchase frequency, and greater predictability over time. As a result, they naturally command significant attention in planning, personalization, and measurement.
This focus is both logical and necessary. Loyalty underpins revenue stability and brand strength. But its role in growth is more nuanced.
Heavy buyers, by definition, represent a smaller portion of the category and often have less headroom to expand their consumption further. Investment in this group tends to sustain and optimize existing behavior, delivering consistent but incremental gains rather than step-change growth.
The implication is not that loyalty is overvalued but that it is often overextended as a growth strategy. Because while loyal customers are essential to protecting value, they are not always where the next wave of growth comes from.
Where the Real Growth Opportunity Sits
Between highly loyal customers and those unlikely to engage sits a larger, more dynamic group: consumers with a moderate probability of choosing the brand. They are not committed, but they are not indifferent. They are responsive, persuadable, and critically, scalable.
The scale imbalance is significant. For a typical 10% share brand, high loyals may represent just 2% of category buyers, while the movable middle can account for closer to 16%. The opportunity is not only in responsiveness, but in reach.
Performance data reinforces this from multiple angles. In one set of MMA analyses, movable middle audiences have shown significantly higher ad responsiveness – up to 5x compared to lower- and higher-probability segments. In separate campaign-level examples, this has translated into materially stronger returns, with one case showing $6.70 ROAS for movable middle audiences versus $1.84 for high loyals.
These studies point in the same direction: the audiences most capable of driving incremental growth are often those still open to influence, not those whose behavior is already fixed.
Why This Changes Planning, Not Just Targeting
This is not just a targeting adjustment. It is a planning shift.
Traditional models prioritize customers based on past behavior: frequency, recency, lifetime value. These are useful indicators of what has already happened. But they are less effective at identifying what could happen next.
A growth-oriented approach looks different. It prioritizes probability of change, not just history of purchase. It asks:
- Who is most likely to switch?
- Who is most responsive to messaging?
- Where can influence still have an effect?
This is the difference between managing customers and moving them.
When growth is defined by movement rather than loyalty alone, it changes how budgets are allocated, how success is measured, and how creatives are developed.
Media decisions begin to prioritize responsiveness over reach alone. Creative strategies focus more on persuasion than reinforcement. Measurement shifts toward incrementality rather than volume.
It also changes how marketers use AI.
Much of the current conversation around AI in marketing focuses on content generation. But its more strategic role may lie in improving decision-making – identifying which audiences are most likely to respond, when they are most likely to act, and how messaging can be adapted to increase that probability.
In that context, frameworks like MMA’s Movable Middles become more than segmentation tools. They become decision systems, helping marketers direct attention and investment toward audiences where change is still possible.
Rethinking the “Best Customer”
Loyal customers remain essential to revenue stability and brand strength. But they are not the only, or even the primary, source of growth.
A more important question for marketers is not who their best customers have been, but who their next customers could be.
That shift in perspective matters. Because growth does not come from reinforcing behavior that is already fixed. It comes from influencing behavior that is still fluid.
The audience most likely to deliver that growth is often not the one most visible in CRM dashboards or loyalty programs. It is the one that sits just beyond them: responsive, persuadable, and frequently under-prioritized.
In a marketing environment increasingly defined by efficiency and accountability, that may be the most valuable audience of all.
