Book · summary

How Brands Grow, the essentials in three minutes.

In 2010, Byron Sharp's How Brands Grow turned much of marketing practice on its head: brands do not grow by making existing customers more loyal, but by reaching more buyers and being easy to choose. Here you will find the key points in text and in an animation, who the author is, what the book changed, where the critics push back and what it means for your content.

Author
Byron Sharp
Published
2010, Oxford University Press
Subtitle
What Marketers Don't Know
Sold
more than 150,000 copies
Translated
into more than 12 languages

The animation

Three minutes, with an English voice-over.

An animation covering the key points, the author, the impact and the criticism, with a British voice-over. Choose subtitles in Dutch, English, French or German.

Read the voice-over text

In 2010, a marketing scientist in Adelaide published a book with an unusually bold subtitle: What Marketers Don't Know. The book was How Brands Grow. Its author, Byron Sharp, had spent years studying how real people actually buy, across many categories and many countries. His conclusion was simple. Brands do not grow mainly by making existing customers more loyal. They grow by winning more buyers. Big brands have more buyers, and those buyers are slightly more loyal. Small brands suffer twice: fewer buyers, and a little less loyalty. Sharp calls this double jeopardy. So where do the extra buyers come from? Mostly from light buyers: people who buy the category, and your brand, only now and then. The famous eighty-twenty rule turns out to be closer to sixty-twenty. The heaviest fifth of a brand's buyers deliver only a little over half of its sales. Nearly half comes from everyone else. So reach matters. Your customers look remarkably like your competitors' customers. Rather than targeting a narrow niche, aim to reach every buyer in the category. Then make the brand easy to buy. Mental availability: being easily thought of when a buying moment arrives. And physical availability: being easy to find, and easy to buy, wherever people shop. People spend very little time thinking about brands, so recognition has to be instant. That is why distinctiveness matters more than differentiation. Consistent colours, logos, shapes and sounds help people notice the brand, and recall it, without having to think. Loyalty still exists, but it is normal, and it is shared. Most buyers of a brand also buy its rivals, roughly in line with their market share. And finally: keep going. Memories fade. A brand that stops advertising slowly disappears from the minds of the buyers it will need tomorrow. The book built on decades of work by Andrew Ehrenberg, and on the research of the Ehrenberg-Bass Institute, which Sharp directs. It has sold more than a hundred and fifty thousand copies, in over a dozen languages. Brands such as Procter and Gamble and Coca-Cola have embraced its principles. In 2016, Procter and Gamble admitted it had targeted too much, and too narrowly. Not everyone agrees. Critics argue that Sharp underplays differentiation, and that laws drawn from stable markets cannot fully explain growth. For content marketers, the lesson is clear. Reach the many buyers who are not buying today. Be distinctive. Be consistent. And be there when the question comes.

The voice-over is an AI voice (Gemini TTS) that does not imitate a real person.

The essence in one sentence

Brands grow mainly by reaching more buyers and being easy to choose, not by making existing customers more loyal.

The key points

Nine insights that turn marketing on its head.

  1. 01

    Growth comes from more buyers

    Brands grow mainly by increasing their penetration: more people buying the brand at least once in a given period. Growing brands mostly gain buyers, and loyalty then rises a little along with them.

    For your content Aim at people who do not know you yet, not just your loyal readers. Measure reach among new people, not only the engagement of fans.

  2. 02

    Double jeopardy

    Small brands are punished twice: they have fewer buyers, and those buyers are also slightly less loyal. Big brands lose customers in proportion to their market share. Drastically increasing loyalty without growing almost never works.

    For your content Do not expect miracles from a customer programme or a community. Loyalty follows growth, not the other way round.

  3. 03

    Most buyers are light buyers

    Most of a brand's buyers buy the category, and the brand, only now and then. The heaviest 20 percent of buyers bring in only a little over half of sales, not 80 percent. The Ehrenberg-Bass researchers speak of 60/20 rather than 80/20.

    For your content Write for people who rarely think of you: clear, recognisable, no prior knowledge needed. Anyone who only comes across your brand occasionally should understand it straight away.

  4. 04

    Reach the whole category

    The customers of competing brands are very similar to one another. So a brand does not grow by choosing a narrow segment, but by reaching all buyers in the category, with a message that works broadly.

    For your content Do not limit promotion to your existing followers or a narrow target group. Use paid reach to get your best pieces in front of the whole category.

  5. 05

    Mental availability

    How easily the brand comes to mind in a buying situation. People do not think long about brands; the brand that comes to mind first for a need, a moment or a question stands the best chance. Jenni Romaniuk later developed this with category entry points: the situations in which people start thinking about buying.

    For your content Your content answers exactly those questions and situations. Link your brand consistently to the moments when your customers need something.

  6. 06

    Physical availability

    How easy the brand is to find and to buy: in shops, online, at the right moment. Without broad availability, no amount of advertising will help.

    For your content Make the next step easy and be findable where people search: in Google, in AI answers and on your customers' channels.

  7. 07

    Distinctive over different

    Buyers see little difference between brands and barely think about them. More important than a unique difference is that your brand is instantly recognisable, through consistent colours, logos, shapes, characters and sounds: distinctive brand assets.

    For your content Use the same recognisable elements in every piece, even when your logo is not in view. Recognition matters more than something new every time.

  8. 08

    Loyalty is normal, and shared

    Loyalty exists, but buyers are almost never exclusive. Most of a brand's buyers also buy from competitors, roughly in proportion to their market share. This is called the duplication of purchase law.

    For your content Do not treat your readers as your property. They read your competitors too, so your content has to keep earning their return.

  9. 09

    Stay visible

    Memories fade. A brand that stops advertising slowly disappears from the memory of the buyers it will need later. Continuous reach works better than an occasional big campaign.

    For your content Choose a rhythm you can sustain. Being visible regularly with recognisable content works better than one big spike followed by silence.

About the author

Byron Sharp

Professor of Marketing Science and Director of the Ehrenberg-Bass Institute

Byron Sharp was born in New Zealand. He studied marketing at the University of Auckland and earned his PhD at the University of Adelaide. He leads the Ehrenberg-Bass Institute for Marketing Science in Adelaide, which since January 2026 has been part of Adelaide University, the merger of the University of Adelaide and the University of South Australia. He has published more than a hundred academic articles and, with Jerry Wind of Wharton, organised two conferences on empirical laws in advertising.

His work builds on Andrew Ehrenberg (1926 to 2010), who published the NBD-Dirichlet model of brand choice with Gerald Goodhardt and Chris Chatfield in 1984. Jenni Romaniuk, research professor at the same institute, co-wrote How Brands Grow Part 2 with Sharp and wrote Building Distinctive Brand Assets (2018). In 2025 Sharp received the Sir Charles McGrath Award from the Australian Marketing Institute and a Lifetime Achievement Award from the European Marketing Confederation.

Born
New Zealand
Education
University of Auckland, University of Adelaide
Position
Professor of Marketing Science
Institute
Ehrenberg-Bass Institute, Adelaide University
Recognition
Sir Charles McGrath Award and EMC Lifetime Achievement Award, 2025

The impact

From theory to the boardroom.

How Brands Grow became one of the most cited marketing books of the past fifteen years. It gave marketers laws instead of opinions, and the argument to keep advertising broadly rather than betting everything on loyalty and narrow targeting. According to Campaign Brief (2025), McDonald's, Nestlé and PepsiCo, among others, work with the Ehrenberg-Bass Institute, and Coca-Cola and Procter & Gamble have applied the principles.

150,000+

copies of How Brands Grow sold.

Source: Campaign Brief, March 2025

12+

languages the book has been translated into.

Source: Campaign Brief, March 2025, and Adelaide University

100+

academic articles by Byron Sharp, one of the most published and cited advertising researchers.

Source: Adelaide University, Byron Sharp profile

A line of research

  1. 1984The NBD-Dirichlet modelGoodhardt, Ehrenberg and Chatfield describe mathematically how buyers choose between brands.
  2. 2010How Brands GrowByron Sharp brings the laws together for marketers, published by Oxford University Press.
  3. 2015How Brands Grow Part 2Jenni Romaniuk and Byron Sharp extend the work to emerging markets, services, durable goods and luxury brands.
  4. 2018Building Distinctive Brand AssetsJenni Romaniuk sets out how to build and protect recognisable brand assets.
  5. 2021Part 2, revised editionEvery chapter updated, with a new chapter on B2B.
We targeted too much and we went too narrow.
Marc Pritchard, chief brand officer of Procter & Gamble, in 2016 (Fortune)

Criticism

Where the critics push back.

  • 1

    Differentiation is underrated

    Felipe Thomaz of Oxford's Saïd Business School argues that the book breaks branding by dismissing differentiation, which he sees as an important driver of growth.

  • 2

    Laws of stable markets

    Ehrenberg's underlying models describe markets in equilibrium. According to Thomaz, they therefore cannot fully explain how a brand grows.

  • 3

    Vague concepts

    Critics say mental and physical availability are not defined sharply enough to be properly tested.

  • 4

    Heavy buyers do matter

    A Dunnhumby study, discussed by Adam Smith and Nick Blair in Campaign Asia, argues that heavy buyers matter more than Sharp suggests.

The original evidence comes mainly from consumer goods. Part 2 extends it to services, durable goods, B2B and luxury.

What it means for content

Six things you will do differently tomorrow.

  1. 01

    Write for the 95 percent who are not buying today, not just for existing customers.

  2. 02

    Answer the questions and situations in which people start thinking about buying.

  3. 03

    Use the same recognisable colours, shapes and phrasing in every piece.

  4. 04

    Put paid reach behind your best pieces, broadly across the category.

  5. 05

    Make the next step easy: from article to tool, conversation or purchase.

  6. 06

    Keep up a steady rhythm instead of an occasional big campaign.

Sources

What this summary is based on.

This summary was written by content-marketing.be and is not affiliated with the author or the publisher. The animation uses no images from the book. Read the book itself for the full body of evidence.

Want to know what broad reach with content delivers?

Simulate your content plan over 36 months, or first read about the 95-5 rule and The Long and the Short of It.

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