Strategic Due Diligence & M&A Lab

Customer Concentration & HHI Calculator

Model customer concentration risk, Herfindahl-Hirschman Index (HHI), valuation multiple discounts, and largest client loss stress tests.

Concentration Engine Revenue & Risk Matrix HHI Principles FAQ

Industry Risk Presets

Load calibrated concentration benchmarks.

Step 1: Revenue, Profitability, Top Account Shares & Cost Structure

Customer Revenue Concentration Inputs

💰 Financial Baseline & Base Valuation

Fixed overhead cannot immediately be cut if a major customer departs, creating severe operating leverage downside.

📊 Top Customer Revenue Shares (%)

Herfindahl-Hirschman Index
2,572 HHI
3.9 effective equal accounts across revenue base
Top 5 Concentration (CR5)
85.0% CR5
Top 1 client accounts for 45.0% of total annual revenue
M&A Valuation Loss
-$7.50M
-2.5x multiple discount (5.5x realized EV)
EBITDA If Top Client Churns
-$2.80M
EBITDA drops 193.3% if largest client churns

Enterprise Valuation Matrix: Revenue ($) vs. Top 1 Client Concentration (%)

Simulates Realized Enterprise Value (EV) and Concentration Multiple Haircut ($ Loss) across scale and account reliance tiers.

Annual Revenue 10% Top 1 Share 20% Top 1 Share 30% Top 1 Share 40% Top 1 Share 50% Top 1 Share

Corporate Strategy Principles

Understanding Customer Concentration

Key risk management, lending, and M&A due diligence principles:

  • The 20% Single-Account Threshold: When any single customer generates over 20% of revenue, commercial lenders and private equity buyers immediately classify the business as concentrated.
  • HHI Department of Justice Guidelines: An HHI below 1,500 indicates an un-concentrated market. An HHI above 2,500 represents extreme concentration where losing one account threatens insolvency.
  • Operating Leverage Downside Trap: Fixed overhead (leases, executive salaries, facilities) cannot easily be eliminated when a whale customer leaves, causing EBITDA to collapse into negative territory.
  • Pricing Power Reversal: Whale accounts possess monopsony bargaining power, demanding volume margin concessions and extended 90-day payment terms that tie up working capital.

Explore firm valuation in the Business Valuation Lab.

Mathematical Formulation

Concentration & HHI equations

CR5 = s_1 + s_2 + s_3 + s_4 + s_5

HHI = ∑ ( s_i^2 ) quad ext{where } s_i ext{ is share %}

Effective_Accounts = 10,000 / HHI

Base_EV = Annual_Revenue × ( EBITDA_% / 100 ) × Base_Multiple

Realized_EV = Base_EBITDA × ( Base_Multiple - Multiple_Discount )

EV_Discount_Loss = Base_EV - Realized_EV

Post_Shock_EBITDA = ( Rev - Lost_Rev ) - ( Fixed_Opex + Post_Shock_Var_Opex )

Evaluate capital structure risk in the Debt-to-Equity Lab.

FAQ

Customer concentration & HHI questions

What is customer concentration risk?

Customer concentration risk occurs when a substantial percentage of revenue is generated by a small number of customers (e.g. Top client > 20% or Top 5 > 50%), making the business vulnerable to severe cash flow shocks if a key client leaves.

How does the Herfindahl-Hirschman Index (HHI) measure concentration?

HHI sums the squares of individual revenue percentage shares: HHI = Sum(s_i^2). Scores below 1,500 indicate healthy diversification, 1,500-2,500 moderate concentration, and above 2,500 severe concentration.

Why do buyers apply a multiple discount for concentrated businesses?

Private equity and strategic buyers discount EBITDA exit multiples (often 1.0x to 3.0x lower) to compensate for the risk of client churn and the cost of debt financing in concentrated revenue bases.

What is the effective number of customer accounts?

Effective Number of Accounts = 10,000 / HHI. It translates skewed account distributions into the equivalent number of identical, equal-sized customer accounts.

Can I export the concentration audit to CSV?

Yes. You can export complete revenue breakdowns, HHI metrics, multiple discounts, client loss stress tests, and 6x5 sensitivity tables as a UTF-8 CSV spreadsheet with formula defense.

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