What this risk is, and why it matters
Customer concentration risk is the exposure that builds when too much revenue rests on too few relationships. A senior executive should care because concentration is invisible while everything is going well and brutal when it is not: the loss, repricing or insolvency of a single dominant customer can remove a large slice of profit overnight, breach covenants, and undermine the very predictability that made the business look strong to lenders and investors.
Legal and regulatory framework
Concentration is primarily a commercial risk, but it carries reporting and governance dimensions. Accounting standards under IFRS and US GAAP require disclosure of significant customer concentrations and credit-risk concentrations in the notes, and listed companies must flag material dependency as a risk factor to regulators such as the SEC or FCA. Competition and procurement rules may constrain how dominant-customer relationships are managed. Auditors increasingly probe concentration when assessing revenue recognition and going-concern judgements.
Typical scenarios and impact
A typical scenario is a customer representing a substantial share of revenue switching supplier, demanding price cuts on renewal, or failing financially. Impacts range from a temporary margin squeeze, through significant earnings reduction and covenant pressure, to existential threat where a single account underpins the business. Even the perception of dependency can depress valuation in a sale or financing, as buyers and lenders discount concentrated revenue against the risk of sudden loss.
Mitigation framework and when to engage an expert
Mitigation combines deliberate diversification of the customer base, stronger contractual protections such as notice periods and minimum commitments, deeper multi-contact relationships, and early-warning monitoring of key accounts. Scenario planning for the loss of each major customer should be routine. Engage commercial and financial specialists to quantify exposure and plan diversification, and counsel to strengthen contract terms, so dependency is reduced steadily rather than addressed only once a critical relationship is already at risk.