How to Measure Buyer Concentration Before Choosing a Market

Who this framework is for

This framework is for strategy, market research, export, and industrial GTM teams comparing candidate verticals or regions where a few buyers, projects, distributors, or corporate groups may control much of the reachable opportunity.

Contents

1 Define concentration for the sales decision 2 Establish the denominator 3 Use the SellersGPT Five-Lens Concentration Test 4 Calculate simple concentration measures 5 Interpret results without false precision 6 Stress-test market resilience 7 Illustrative example 8 Common mistakes 9 What this does not mean 10 Common questions 11 Sources and methodology

1. Define concentration for the sales decision

Buyer concentration asks: How much of the reachable opportunity, influence, or access depends on a small number of independent buying centers? Define three boundaries first:

• Product boundary: the exact product and substitute set relevant to buyers.

• Geographic boundary: the serviceable region, not necessarily a country.

• Buying unit: facility, parent, procurement group, project owner, distributor, or another unit with real control. If ten facilities share one centralized procurement organization, ten account rows may represent one economic buyer. If one parent allows plants to purchase independently, parent-level concentration may overstate dependency. Validate governance rather than assuming it.

2. Establish the denominator

Official business counts can help estimate establishments by industry and geography in the United States and Canada. They do not disclose complete firm-level buyer shares and cannot by themselves establish commercial concentration. U.S. Census Bureau - County Business Patterns and Statistics Canada - Canadian Business Counts Choose the best available denominator: Denominator Useful when Main limitation Verified accounts Purchase potential is roughly similar Treats small and large buyers equally Facilities or capacity Application scales with production footprint Capacity data may be incomplete or incomparable Estimated category spend Credible category-specific estimates exist Often modeled, confidential, or outdated Relevant project value Market is project-driven Timing and award probability are volatile Units consumed or installed base Product use can be estimated consistently Requires strong technical assumptions Never call a proxy "market share" without explaining the denominator and coverage.

3. Use the SellersGPT Five-Lens Concentration Test

Measure five distinct dependencies: Lens Question Example risk Account How much depends on the largest named buyers? One account dominates opportunity Parent How many accounts collapse under common control? Apparent diversity is duplicated Geography How much sits in one region or corridor? Local disruption or costly coverage Channel How many distributors, reps, or platforms control access? One gatekeeper can block entry Trigger How much depends on one project, renewal cycle, or regulation? Demand arrives in irregular bursts An additional buying-group lens can test whether the same engineering consultant, contractor, or approved-vendor system influences multiple nominally independent accounts.

4. Calculate simple concentration measures

Count concentration Calculate the share of verified accounts controlled by the largest independent parents: Top-N account share = accounts controlled by the largest N parents / all verified accounts This is transparent but assumes equal account weight. Weighted Top-N share When a defensible commercial proxy exists: Top-N weighted share = estimated opportunity for largest N buyers / total estimated opportunity Disclose the proxy, period, coverage, missing-data treatment, and whether estimates come from official facts, first-party disclosures, or internal modeling. HHI-style descriptive index The U.S. Department of Justice defines the Herfindahl-Hirschman Index as the sum of squared market shares. It rises as the number of firms falls or their shares become more unequal and reaches 10,000 for a single firm with 100 percent share. DOJ - Herfindahl-Hirschman Index For internal market-entry analysis: Descriptive buyer HHI = sum of each buyer's estimated percentage share squared Use this only when the shares cover the same defined market and are sufficiently credible. Label it an HHI-style descriptive calculation, not an official antitrust determination. The DOJ and FTC merger guidelines apply concentration tools within legal merger review and depend on relevant-market definition and evidence. Their thresholds are not SellersGPT market-entry rules. The agencies also explain that the probative value of structural measures depends on whether the products and market used match the competitive concern. DOJ - Calculating Market Shares and Concentration Published industry concentration ratios The U.S. Economic Census publishes concentration-ratio tables for selected sectors, including shares attributed to groups such as the largest four firms. These describe producer-side industry structure under Census definitions; they do not directly measure the concentration of your target buyers. U.S. Census Bureau - 2022 Economic Census Concentration Ratios

5. Interpret results without false precision

Use three qualitative bands defined for the project, not universal thresholds:

• Distributed: losing any one account, parent, region, or channel leaves the test viable.

• Dependent: a small group materially shapes the opportunity; named-account and risk plans are required.

• Fragile: one account, parent, channel, or trigger can invalidate the market thesis. For each band, record:

• calculation and source coverage;

• material missing buyers;

• centralized versus decentralized purchasing;

• switching barriers and approved-vendor rules;

• evidence that the buyer can actually purchase the offer;

• route-to-market consequences. A concentrated market may support a focused enterprise strategy if the team has access, proof, patience, and service capacity. It may be unsuitable for a high-volume cold-outreach motion.

6. Stress-test market resilience

The Largest-Buyer Removal Test asks what happens if the largest one, three, and five buying groups are unavailable. Scenario Question Remove largest 1 Is the remaining universe still worth a test? Remove largest 3 Can the pipeline thesis survive realistic non-access? Remove largest 5 Does the route to market still work? Remove largest channel Can buyers be reached another way? Delay major trigger Can demand be supported by replacement or other cycles? Also test whether the largest buyers are already customers, contractually restricted, tied to incumbents, beyond service coverage, or governed by inaccessible procurement. A large theoretical buyer may contribute zero reachable opportunity.

7. Illustrative example

Illustrative example. All accounts, shares, and decisions are fictional and do not represent a customer or forecast. An industrial supplier identifies 120 relevant facilities. At first, the market appears distributed. Identity resolution shows that 46 facilities belong to four parent groups. Estimated capacity further suggests that the largest two parents account for a disproportionate share of the addressable application. The team classifies the market as Dependent, not Fragile, because:

• the remaining independent facilities still support a bounded test;

• purchasing is partly decentralized;

• two distributors provide alternative access;

• replacement demand is not tied to one project. The sales design changes: named-parent account plans cover the largest groups, while a regional program tests the distributed remainder. The team does not publish its internal proxy shares as official market statistics.

8. Common mistakes

Counting facilities without resolving parents This inflates apparent independence. Link ownership and confirm purchasing authority. Using company revenue as category spend Total revenue may have little relationship to consumption of the target product. Use it only as a disclosed, weak proxy if necessary. Applying DOJ thresholds as commercial rules Antitrust guidance serves a legal purpose. Use concentration math descriptively and create decision bands appropriate to the GTM question. Ignoring channel concentration Many buyers may still be reachable only through a few distributors, contractors, or approved platforms. Hiding missing data inside a precise index An index built on incomplete shares can be misleading. Show coverage and uncertainty.

9. What this does not mean

• Concentration does not prove market power, antitrust risk, or illegality.

• A distributed account count does not guarantee distributed spend.

• High concentration does not automatically mean "do not enter."

• Low concentration does not guarantee easy access or good economics.

• The framework does not replace legal or competition advice.

10. Common questions

Do I need exact buyer spend? No, but the weaker the proxy, the more qualitative the conclusion should be. Count-based, capacity-based, and project-based views can be triangulated. Should I calculate concentration by facility or parent? Calculate both when buying authority is unclear. Then validate whether specifications, contracts, and budgets are centralized. Is Top-5 share enough? It is a clear first measure. Add a distribution-wide index only when share estimates are credible and the added complexity changes the decision. What if distributors hide end-buyer identities? Treat channel concentration and information dependence as separate risks. Validate alternative channels and contract reporting expectations before entry.

11. Sources and methodology

Sources 1 U.S. Census Bureau - County Business Patterns API. Used for aggregate establishments and employment by geography and industry. Accessed August 24, 2026. 2 Statistics Canada - Canadian Business Counts, Table 33-10-1097-01. Used for Canadian employer-location counts by subnational geography and NAICS. Accessed August 24, 2026. 3 U.S. Department of Justice - Herfindahl-Hirschman Index. Used for the official HHI definition and mathematical properties. Accessed August 24, 2026. 4 U.S. Department of Justice - Calculating Market Shares and Concentration. Used to clarify the dependence of structural measures on relevant-market and evidence choices. Accessed August 24, 2026. 5 U.S. Census Bureau - 2022 Economic Census Concentration Ratios. Used to distinguish published producer-side concentration ratios from buyer concentration. Accessed August 24, 2026. SellersGPT analysis and framework The Five-Lens Concentration Test, Distributed/Dependent/Fragile bands, and Largest-Buyer Removal Test are original SellersGPT recommendations. The HHI formula is an official concentration concept cited above; its suggested descriptive use here is editorial and not a legal conclusion. Update policy Review annually and whenever ownership, market boundary, account universe, capacity proxy, route to market, or source coverage changes. Recalculate time-sensitive measures from preserved inputs.