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The 95-5 rule is one of B2B marketing's favorite soundbites. At any given moment, the argument goes, only 5% of a market is in-market to buy, while the other 95% is not. It appears regularly in board meetings, brand strategy decks and arguments about where marketing budgets should go.
The problem is that, in many fast-growing B2B technology categories, the 95-5 rule doesn't describe the market very well. The difference isn't marginal. Depending on how quickly a category is growing, the proportion of buyers entering the market for the first time can be several times higher than the rule suggests.
That's the argument Dale W. Harrison and Liam Moroney explore in Episode 4 of B2B Effectiveness: Evidence-Based Marketing Ideas for B2B Practitioners. The 95-5 rule isn't necessarily wrong. It is based on a particular set of conditions, and those conditions change significantly when a market is growing or shrinking.
Where the 95-5 rule actually comes from
The principle traces back to Andrew Ehrenberg's NBD model of purchase frequency and decades of research across thousands of products. The research found that, within a category, a relatively small number of buyers purchase frequently while a much larger number purchase occasionally. At any particular point in time, that means only a small proportion of the market is actively buying. So far, so intuitive.
The important detail is the type of market the model describes. It applies to stationary markets, where the category is neither growing nor shrinking and purchases are largely repeat purchases.
Laundry detergent is a straightforward example. People aren't continually entering the category for the first time; they are replacing a product they've bought before. That is very different from a B2B technology category that is expanding and bringing new buyers into the market every year, or a declining category where the pool of repeat buyers is getting smaller.
Why growing markets break the rule
Consider the iPod when it launched. Every unit sold in its first month went to someone who had never previously bought an MP3 player. The category was new, so 100% of those buyers were first-time buyers.
That's an extreme example, but the same mechanism operates in any growing category. As new buyers enter the market, they sit alongside existing customers who are making repeat purchases. The faster the category grows, the larger the proportion of potential buyers who are there for the first time.
Harrison uses the CRM market in the early 2000s to illustrate the point. The category was growing at around 100% a year, and under those conditions he estimates that roughly a quarter of the market could be in-market at any given time. That's a long way from 5%.
Even today, with US CRM market growing at a much more modest 13.5% annually, Harrison estimates that 30-40% of active buyers are still first-time buyers.
The practical implication is important. The growth rate of a category provides useful information about the makeup of its buying audience. If a market is expanding rapidly, assuming that only 5% of potential buyers are in-market can significantly understate the size of the opportunity.
The trouble with the famous 50-50 split
The same question of context applies to another familiar piece of B2B marketing wisdom: the recommendation from Binet and Field that marketing investment should be divided roughly 50-50, or in some cases 60-40, between brand and performance activity.
Harrison's criticism isn't necessarily of the principle itself, but of how broadly the finding is applied. The research draws heavily from large, established companies with substantial marketing budgets and the resources to enter marketing award competitions. That creates a selection effect that can make the findings less representative of smaller companies or businesses operating in rapidly growing categories.
The result is a familiar problem in B2B marketing: data from companies operating under very different market conditions gets combined into a single ratio, which is then treated as if it were a universal rule.
One of the more striking examples Harrison points to is the number of large B2B technology companies that appear to have reached significant scale without relying heavily on traditional brand advertising. Of the roughly 500 B2B technology companies generating more than $1 billion in annual revenue, he estimates that around 70% reached that milestone without running a single brand ad. They grew entirely on performance marketing.
Salesforce is a useful illustration of the broader pattern. The company did not make a significant investment in brand advertising until it was around 20 years old, and only once CRM category growth began to flatten out.
Why some of the biggest brands on earth never advertise at all
The pattern isn't unique to technology.
Walk into an American supermarket and you'll find 4,000-5,000 unique brands on the shelves – 60-80% of which have never run a single piece of advertising in their entire history. Their only marketing is shelf placement, packaging, and the occasional in-store display: the retail equivalent of performance marketing, reaching buyers only at the exact moment they're already in-market.
Brand marketing earns its keep in a very specific situation: long repurchase cycles. If your buying cycle is three, four, five years, that's a long time for a prospect to forget you exist – memories decay to nothing within a few weeks to a few months without reinforcement. That's why market leaders like Salesforce, who can count on roughly a third of all buyers having already used their product, have a durable memorability advantage that a small, fast-growing challenger simply can't buy its way into with a single campaign.
The contrast Dale draws is exterminators versus DUI attorneys. Home exterminators lean almost entirely on brand – broad, generic marketing that stays top-of-mind for the rare moment someone needs one. DUI attorneys do something much sharper: heavy use of memorable mnemonics and billboards concentrated in bar districts, aiming to be remembered at the exact moment of arrest – arguably the most precisely targeted “in-market” moment in all of marketing.
The point isn't that one approach is inherently better. The value of brand and performance activity depends heavily on the buying cycle, the structure of the market and how likely someone is to need the product at a particular moment.
A law, not a soundbite
The 95-5 rule is therefore better understood as a model with conditions than as a universal constant.
Dale's analogy is gravity: it behaves differently on the Moon, Earth and Jupiter, but the underlying laws of physics haven't changed. What changes is the value you calculate in each context.
The 95-5 rule works in much the same way. It's a useful baseline, but the conditions of the market determine how closely that baseline reflects reality. Rising markets are like wind at your back; falling markets are like friction. F still equals ma – you just have to account for the forces acting on top of it.
That has a direct implication for lead generation and scoring: if a category is growing at 25%, for example, the proportion of buyers entering the market is going to look very different from a static category. A qualification model that ignores that context is starting with an incomplete picture of the opportunity.
And market context is only one part of that picture. The next question is what happens when you add the seller into the equation. Two companies can operate in the same market, target the same type of customer and still have very different chances of winning.
That's where Dale and Liam go next in Episode 5: “The ICP” Is Not Necessarily Your ICP, exploring the role of Buyer-Seller Fit in determining where a company's real opportunity lies.
