Concentration Risk

Concentration risk has been recognized as a critical strategic concern since the earliest days of portfolio theory. While Harry Markowitz formalized the mathematics of diversification in his 1952 paper on portfolio selection, the underlying principle — that putting all your eggs in one basket invites disaster — has guided prudent business practice for centuries. In strategic management, concentration risk extends beyond financial portfolios to encompass customer concentration, supplier dependence, geographic exposure, and product-line reliance.

The strategic importance of concentration risk cannot be overstated. When a company derives a disproportionate share of its revenue from a single client or market, it effectively cedes control over its destiny to external forces. Research by the Harvard Business Review has shown that companies where a single customer accounts for more than 25% of revenue trade at lower valuation multiples, reflecting investor awareness of this vulnerability. The risk is not merely theoretical: GT Advanced Technologies filed for bankruptcy in 2014 after Apple cancelled a major sapphire glass contract that represented the bulk of its projected revenue.

Real-world examples of concentration risk abound across industries. Nokia's near-total dependence on mobile handsets left it devastated when smartphones disrupted the market after 2007. Conversely, companies like Amazon have systematically reduced concentration risk by diversifying from e-commerce into cloud computing (AWS), advertising, and entertainment. AWS alone grew to represent a major profit center, insulating Amazon from margin pressure in its retail operations.

For practitioners, managing concentration risk requires ongoing portfolio analysis across multiple dimensions: revenue by customer, geographic exposure, supplier dependence, and product-line contribution. The goal is not to eliminate concentration entirely — focused strategies can deliver superior returns — but to understand and consciously accept the trade-offs involved. Companies should establish threshold triggers, such as no single customer exceeding 15-20% of revenue, and develop contingency plans for scenarios where key dependencies are disrupted.

Mitigating concentration risk often involves deliberate diversification initiatives, but these must be balanced against the benefits of focus and specialization. The optimal approach varies by industry and competitive context. A defense contractor may accept high customer concentration with the U.S. government as an inherent feature of its business model, while a consumer products company would view similar concentration as an urgent strategic liability requiring immediate action.