With millions of products and thousands of categories, knowing “who’s winning” on Amazon is tough.

For Amazon sellers, agencies, and brand managers, understanding market share by category is like reading the scoreboard of a game – it shows which brands lead and how everyone else stacks up.

Here you will learn why category market share matters, how to find it (using tools like SmartScout), and what insights you can gain about which brands are winning and why.
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Why Market Share by Category Matters

Market share is essentially the percentage of total sales in a category that a brand accounts for. It tells you who the market leaders are and how far ahead they are. This information is invaluable for several reasons:
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• Benchmarking Performance: Brands use market share as a scorecard to report to executives and investors. For example, is $10 million in sales good or bad? That depends on the total category – market share data helps justify performance and set realistic goals.
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• Understanding Market Size: If a niche is $5 million/year and you have $1 million, you know you’re 20% of that market. Knowing the market ceiling prevents chasing unrealistic targets.
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• Competitive Insights: Market share data lets you identify the top competitors in a category and understand why they’re winning. It reveals if one rival dominates or if the field is fragmented. As SmartScout notes, brands want to win – and seeing the leaders helps you strategize how to take share from them.
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• Strategic Decision Making: Knowing who owns the category guides resource allocation. If competitors outpace you, should you invest more in PPC ads, expand your product line, or find a new niche? A bird’s-eye view of the market informs these long-term decisions.
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Market share data will not directly raise sales, but it strengthens strategy. Big brands use it to measure success, analyze competitors, and spot trends for an edge.
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The Challenge of Getting Amazon Market Share Data

Despite its importance, category-level market share on Amazon is not easy to obtain. Amazon doesn’t publicly report what percentage of a category each brand holds. Traditionally, only expensive third-party reports could tell you “Brand X has Y% of Category Z.”

In fact, many market share services hide behind sales calls and paywalls, with a single report costing $30K or more. It’s no surprise that thousands of brands pay hefty fees for this data every year.

Why so costly? These reports compile sales estimates across millions of ASINs and often require complex modeling. However, paying $30K for a static report is often overkill – especially for smaller sellers.

As one SmartScout analysis put it, brands are overpaying, and there are now cheaper, more efficient ways to get Amazon market insights without breaking the bank.

This is where tools like SmartScout come in, democratizing market share data for everyday Amazon professionals. Instead of a one-time report, you can get continuous visibility into categories and brands at a fraction of the cost.
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SmartScout’s Subcategories Tool: Market Share at Your Fingertips

SmartScout is an Amazon intelligence software designed to reveal who’s winning in every niche. One of its flagship features is the Subcategories tool, essentially a catalogue of Amazon’s 40,000+ subcategories. SmartScout breaks down Amazon’s entire category hierarchy – from top-level categories down to micro-niches – showing estimated revenue and brand market share in each one.

Key capabilities of SmartScout’s Subcategories tool include:
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• Massive Category Coverage: Over 42,000 subcategories across 11 Amazon marketplaces worldwide are tracked. Whether you sell on Amazon US, UK, India, Canada, or European markets, you can analyze category share in your locale.
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• Category Insights at a Glance: For any category or subcategory, see metrics like total monthly revenue, number of sellers, average price, and Amazon’s own retail share. This gives a quick sense of market size and competition in that niche.
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• Brand Market Share Breakdown: With one click, SmartScout lists the top brands in any subcategory and their revenue share of that subcategory. In other words, you can instantly find out which brand is #1, #2, #3, etc., and what portion of sales they each capture.
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• Drill-Down to Products: SmartScout even lets you see every product under a subcategory, so you can connect the dots – for example, seeing which ASINs drive a brand’s dominance in that category.
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• Historical and Comparative Data: Beyond current share, you can track trends like a subcategory’s growth or a brand’s trajectory over time (trailing 12 months, growth rates, etc.). This helps identify up-and-coming challengers or declining leaders.
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SmartScout provides a 360° view of any category. It’s designed to give Amazon professionals the kind of competitive intelligence that was once reserved for big brands with big budgets. Subcategories tool “allows you to see sales and brand data across an entire category – stacking you up against all your competitors at the brand level”. Instead of looking at isolated products, you get the complete picture of the market.

Example: Say you operate in the “Protein Bars” subcategory. Rather than guessing who the top players are, SmartScout will show you something like: Brand A – 30% share, Brand B – 15%, Brand C – 10%, etc., along with the rest of the market. Immediately, you know the pecking order and how far ahead Brand A is. This context is critical to understand your place in the Amazon market.
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What Brands Are Winning? Examples of Category Leaders

Let’s look at a few examples of Amazon category leaders – which brands are winning, and why they hold their top positions. These examples show how market share data provides insight into brand dominance:

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Table: Examples of Amazon subcategories and their top brands’ market share. (Sources: SmartScout data and industry reports.)

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These cases highlight different dynamics of why brands win in their categories:
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• Scale and Trust: Quest Nutrition’s lead in protein bars shows how being a trusted, established brand creates a virtuous cycle. They can generate high sales with relatively lower advertising spend because customers seek them out. Leaders often enjoy higher profit margins and lower cost of customer acquisition as their market share increases. In Amazon’s marketplace, the biggest brands keep getting bigger – success breeds more success.
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• Platform Advantage: AmazonBasics in batteries demonstrates the power of Amazon’s ecosystem. Amazon gave its private label prime real estate and competitive pricing, quickly dominating a category where brand loyalty is moderate. Within a few years of launch, AmazonBasics overtook legacy brands online. This teaches sellers that Amazon itself can be a formidable “brand” in some categories (especially commodities).
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• Innovation and Differentiation: The Poppi vs. Olipop battle shows that even in categories with no single Goliath, innovators can rapidly gain share. Both brands identified a growing demand (low-sugar, probiotic soda) and executed unique branding. By expanding the category and engaging customers in new ways, they carved out large slices for themselves. When no incumbent owns over half the market, there’s room for multiple winners – and branding strategy can tilt the balance.

It’s also insightful to notice when a category is fragmented versus concentrated. If one brand holds, say, 70% share, any challenger has an uphill fight. But if the leader has 20% and many others have 10-15%, the market is wide open. SmartScout helps reveal these structures at a glance, so you can decide whether to enter a niche or how to position against the leader. In SmartScout’s own advice: look for subcategories where “there is a wide distribution of brands spread across a lot of market share” – those niches may indicate opportunities since no single brand satisfies all customers. Conversely, if a single brand controls a subcategory, you might need a highly differentiated strategy (or choose an easier battleground).

Turning Market Share Insights into Action

Knowing the numbers is just the start – the real goal is to apply these insights to your Amazon business. Here are some ways Amazon professionals can leverage category market share data:
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• Sellers (Private Label): Identify niches where customers aren’t fully satisfied and no brand dominates. For example, if you find a subcategory with mediocre reviews across products and a fragmented share distribution, it’s a signal that a new entrant (with a better product) could capture share. Use SmartScout to spot these gaps, then launch a product to fill them.
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• Brands & Brand Managers: Benchmark your brand’s share and track it over time. Are you gaining on competitors or slipping? If a rival’s share is growing, dig into why – do they have more SKUs, lower prices, better SEO/ads? Market share changes can reveal successes or issues in your strategy. Also, communicate your share to executives as a metric of market position (e.g., “We’re the #2 brand in our category with 15% share” is a powerful statement for stakeholders).
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• Agencies and Consultants: Use market share data as a pitch tool and roadmap. You can audit a prospective client’s category to show them, “Your brand has 5% share, while the leader has 25%. Here’s what they’re doing right (more reviews, broader catalog, aggressive PPC) and how we can close the gap.” It quantifies the growth opportunity and justifies your proposed tactics. In fact, SmartScout’s Market Share insights are often used by marketing agencies to craft pitch-perfect strategies for brand clients.
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• Advertisers/PPC Specialists: Pay attention to the relationship between ad spend and market share. If the top brand in the category isn’t the one spending the most on ads, it indicates organic strength (like Quest in protein bars). On the other hand, a challenger heavily outspending others could be trying to buy growth. SmartScout even offers an Ad Spend Share metric to compare ad investment vs. sales share. Use this to calibrate your advertising – are you overspending for minor gains, or could a smart campaign boost your share significantly?
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• Product Development: A brand’s market share by subcategory can highlight where to expand next. If you already lead one niche, the data might show adjacent subcategories where no clear winner exists – a natural area for you to introduce a new product line. On the flip side, if a competitor dominates a sub-niche you’re not in, consider why – is it a product type you should add, or is their dominance a moat you should avoid? Let the market share distribution guide your roadmap.
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Conclusion: Gaining the Edge with SmartScout

In Amazon, knowing market share by category and which brands are winning lets you act strategically instead of flying blind. SmartScout’s Subcategories tool helps you monitor competitors continuously, spot leaders’ advantages and upstart opportunities, and uncover the story behind the numbers without paying for a one time report.

Ready to find out who’s winning your category? Don’t leave it to guesswork.

SmartScout gives you the data and clarity to make the right moves on Amazon’s battlefield. Book a demo with SmartScout today and see how brand market share insights can turbocharge your Amazon strategy.

By understanding the market and your place in it, you’ll be equipped to take action – whether that’s toppling the category king or becoming one yourself.