The Herfindahl-Hirschman Index (HHI) is the gold standard for measuring market concentration in economics, used by the U.S. Department of Justice and the Federal Trade Commission to evaluate merger impacts. In Amazon niche-analyse, HHI provides an objective, numerical answer to one of the most important questions a verkoper can ask: how concentrated is this market, and is there room for a new entrant?
Unlike subjective assessments of concurrentie ("this looks competitive" or "there seem to be a lot of verkopers"), HHI reduces market structure to a single number that can be consistently compared across niches, categories, and marketplaces.
The HHI Formula
Herfindahl-Hirschman Index
Where S = market share of each verkoper (as a whole number, not decimal)
Each verkoper's market share is expressed as a percentage (e.g., 25 for 25%, not 0.25), squared, and then all squared values are summed. The result ranges from near 0 (perfectly competitive, infinite verkopers with equal shares) to 10,000 (monopoly, one verkoper with 100% share).
Understanding the Scale
The DOJ defines three concentration zones:
- HHI below 1,500: Unconcentrated (competitive) market. Multiple verkopers compete actively, no single player dominates, and new entrants face manageable barriers.
- HHI 1,500 to 2,500: Moderately concentrated market. A few verkopers hold significant share, but the market is not locked down. Entry is possible with differentiation.
- HHI above 2,500: Highly concentrated market. One or a few verkopers dominate. Entry requires significant investment and carries high failure risk.
For Amazon niche-analyse specifically, we refine these thresholds based on observed outcomes across thousands of product launches. The profitable niche criteria recommend an ideal HHI range of 800-1,500 for new product entry.
How to Berekenen HHI for an Amazon Niche
Step 1: Define the Niche Boundary
HHI calculation requires a clearly defined market. On Amazon, this means identifying the specific search term that defines your competitive set. "Yoga mats" and "extra thick yoga mats" are different niches with different HHI values. Use the primary keyword you would target for PPC campaigns as the niche boundary.
Step 2: Estimate Monthly Revenue for Top Sellers
For the top 20-30 verkopers appearing on pages 1-2 of the search results for your primary keyword, estimate monthly omzet. Methods include:
- BSR-based estimation: Amazon's Best Sellers Rank (BSR) correlates with daily unit sales. Tools like Jungle Scout, Helium 10, and Keepa provide BSR-to-sales conversion models. Multiply estimated daily units by price to get monthly omzet.
- Brand Analytics (for registered verkopers): Provides click share and conversion share data that can be used to estimate relative omzet distribution.
- Manual tracking: Monitor inventory levels over 7-14 days using the "add 999 to cart" method (less reliable for FBA verkopers with large inventories, but useful for triangulation).
Step 3: Berekenen Market Shares
Convert estimated omzet to market share percentages. Total market omzet = sum of all tracked verkopers' omzet. Each verkoper's share = (verkoper omzet / total omzet) x 100.
Step 4: Square and Sum
Square each market share value and sum all squared values. This is the HHI.
Worked Example: Bamboo Cutting Boards
Let us calculate HHI for the "bamboo cutting board" niche on Amazon US:
| Seller | Est. Monthly Revenue | Market Share | Share Squared |
|---|---|---|---|
| Brand A | $85,000 | 22.4% | 501.8 |
| Brand B | $62,000 | 16.3% | 265.7 |
| Brand C | $41,000 | 10.8% | 116.6 |
| Brand D | $38,000 | 10.0% | 100.0 |
| Brand E | $29,000 | 7.6% | 57.8 |
| Brand F | $22,000 | 5.8% | 33.6 |
| Brand G | $18,000 | 4.7% | 22.1 |
| Brand H | $15,000 | 3.9% | 15.2 |
| Brands I-R (10) | $70,000 | 18.4% combined | ~43.0 |
| Total | $380,000 | 100% | 1,155.8 |
HHI = 1,156. This falls in the unconcentrated zone, indicating a competitive market structure that is accessible to new entrants. The leading brand holds 22.4% share -- significant but not dominant -- and omzet is distributed across multiple players. This is a healthy competitive environment for a new entrant with a differentiated product.
Worked Example: Instant Pot Accessories
Compare with the "instant pot accessories" niche:
| Seller | Est. Monthly Revenue | Market Share | Share Squared |
|---|---|---|---|
| Brand A | $210,000 | 38.2% | 1,459.2 |
| Brand B | $125,000 | 22.7% | 515.3 |
| Brand C | $78,000 | 14.2% | 201.6 |
| Brand D | $52,000 | 9.5% | 90.3 |
| Brand E | $35,000 | 6.4% | 41.0 |
| Brands F-P (11) | $50,000 | 9.1% combined | ~12.0 |
| Total | $550,000 | 100% | 2,319.4 |
HHI = 2,319. This falls in the moderately concentrated zone, approaching the highly concentrated threshold. Two brands control 61% of the market. While entry is not impossible, it would require significant differentiation and PPC investment to capture even 5% market share. The risk-reward ratio is less favorable than the bamboo cutting board example.
HHI Limitations and Adjustments for Amazon
While HHI is powerful, applying it to Amazon niches requires understanding its limitations:
Limitation 1: Revenue Estimation Accuracy
HHI quality depends entirely on the accuracy of omzet estimates. BSR-based tools have error margins of 20-40%, which propagates into the HHI calculation. To mitigate this, track BSR data over 30+ days rather than relying on point-in-time snapshots. The longer the observation period, the more accurate the omzet estimates.
Limitation 2: Niche Boundary Definition
The calculated HHI changes significantly depending on how broadly or narrowly you define the niche. "Cutting boards" will produce a lower HHI than "bamboo cutting boards with juice grooves" because the broader definition includes more verkopers. Always use the search term that matches your intended PPC targeting for consistency.
Limitation 3: Variation Listings
Amazon parent-child variation listings (multiple sizes/colors under one ASIN) aggregate reviews and sales data. A verkoper with 5 variations appears as one entity in HHI calculations but actually covers multiple market segments. Adjust by separating variation-level omzet when possible.
The RIDGE Adjusted HHI
In our niche-analyse reports, we calculate an adjusted HHI that accounts for these limitations by using 30-day rolling BSR data, normalizing for variation listings, and weighting recent sales more heavily than historical data. This produces a more actionable concentration metric than raw HHI calculations.
Get Precise HHI Analysis for Your Niche
RIDGE calculates adjusted HHI using 30-day rolling BSR data and proprietary omzet estimation models, providing a more accurate concentration metric than point-in-time snapshots.
Order Concentration AnalysisUsing HHI in Decision Making
HHI should never be used in isolation. It is one component of a comprehensive niche evaluation that includes demand validation, profitability modeling, and risk assessment. Here is how to integrate HHI into your decision framework:
- Berekenen HHI as part of concurrentie assessment -- Step 2 of the 7-step validation framework.
- Cross-reference with other saturation signals -- Average review counts, CPC levels, brand concentration, and margin trends as described in our 5 saturation signals guide.
- Compare across marketplaces -- The same niche may have an HHI of 2,800 in the US but 1,200 in Duitsland. This marketplace-level comparison can redirect your entry strategy to a less concentrated geography.
- Track over time -- Rising HHI indicates increasing concentration (consolidation). Declining HHI suggests new entrants are successfully capturing share (opportunity window). Monitor quarterly.
The most profitable product launches consistently target niches with HHI in the 800-1,500 range: competitive enough to confirm market viability, but distributed enough to allow new entrants to capture meaningful share. Combined with the other criteria in our profitable niche-analyse, HHI provides the structural foundation for data-driven product selection.