What dependence means
A company is dependent on a supplier when losing that supplier would be hard to absorb. The difficulty might come from the supplier’s share of purchases, the lack of alternatives, the time and cost of switching, or the importance of the item to the final product. Concentration risk is the broader idea that too much of a company’s supply sits with too few suppliers, regions, ports or routes, so a single event can cause outsized harm.
Dependence is not automatically bad. Close partnerships with a few suppliers can bring efficiency, and many companies choose them deliberately. The risk lies in being dependent without noticing, or without a plan for what happens if things go wrong.
Where concentration shows up
Concentration can hide in several forms:
- One supplier. The most obvious case, where a single vendor provides an item, either by choice or because no one else can. The choice itself is weighed in single sourcing versus multiple sourcing.
- One region. Several suppliers that are physically close together share exposure to weather, power cuts, regional unrest or local regulation. An earthquake, flood or lockdown can hit them all at once.
- One upstream source. Different suppliers may rely on the same maker of a key component or material, so apparent diversity disappears a tier or two back. Finding this requires supply chain mapping.
- One route. Goods from various suppliers might pass through the same port, canal or border crossing. A closure at one of the maritime chokepoints or a bout of port congestion can affect many shipments at once.
- One mode or carrier. Dependence on a single transport provider or on a single type of transport can leave a company stuck if capacity tightens.
- One customer, from the supplier’s side. If a supplier sells most of its output to the buyer, the supplier itself may be fragile, which in turn endangers the buyer.
Dependence runs both ways
A buyer that makes up most of a small supplier’s business holds power over it, but also carries responsibility: if the buyer cuts orders, the supplier may fail. Conversely, a supplier that is the only source for a critical item holds power over the buyer, which can show up in pricing or allocation during shortages. Understanding who needs whom more helps predict behavior during stressful periods.
How to gauge exposure
There is no single formula, but buyers commonly ask questions such as:
- What share of spend on this item goes to the largest supplier?
- How long would it take to qualify and ramp up a replacement?
- What would a stoppage cost per week, in lost sales and expedited freight?
- How much stock is on hand, and how many weeks would it cover?
- Do the suppliers share a location, an upstream source or a shipping route?
A rough ranking of items by importance and replaceability usually reveals a short list that deserves attention, while most items matter less. The goal is to focus effort, not to analyze everything equally.
A hypothetical illustration
Suppose a company buys 100,000 units a year of a key part and 80,000 come from one supplier. That supplier accounts for 80 percent of volume, a simple measure of concentration. If it stopped shipping and the company held four weeks of stock, the buyer would have roughly four weeks to arrange alternatives. If a replacement takes twelve weeks to qualify, there would be a gap of about eight weeks (12 minus 4), during which the company would need substitutes, rationing or temporary shutdowns. The figures are invented, but the method of comparing stock cover with replacement time is a useful way to see whether exposure is tolerable.
Why concentration builds up
Concentration often grows gradually rather than by a single decision. Price competition favors the cheapest supplier, successful relationships attract more volume, and efficiency programs reduce the number of vendors. Cluster effects also matter: whole industries may gather in one region because of shared skills and infrastructure, so even independent choices can lead to the same place. Companies pursuing lean supply chains may reduce buffers at the same time, which compounds the exposure.
Events have repeatedly shown the consequences. The COVID-19 pandemic and later disruptions revealed how many supply chains depended on narrow sources or routes, and the effects of climate change on weather, rivers and ports add further reasons to look at geographic spread. The long-term pattern of such events is uncertain, which is itself a reason for caution.
Ways to reduce risk
None of these is free, and each involves trade-offs:
- Add or qualify a second source. Even if it receives a smaller share, an approved alternative shortens the path to recovery.
- Diversify geography. Choose suppliers in different regions to avoid shared local hazards, weighing the effects discussed in nearshoring, reshoring and offshoring.
- Hold buffer stock. Extra safety stock for critical items buys time, at the cost of money tied up and storage.
- Redesign. Use more standard parts or allow alternative materials so substitution becomes easier.
- Sign longer agreements. For unavoidable dependence, contracts with capacity commitments can offer some security, though they cannot remove risk entirely.
- Improve visibility. Better supply chain visibility helps spot trouble earlier.
- Support the supplier. Where the supplier is critical, helping it improve resilience or financial stability can protect the buyer too.
Making it part of routine management
Concentration risk is easiest to handle when it is checked regularly, not only after a disruption. Including it in supplier reviews, as part of ordinary supplier management, keeps it in view. It also fits within a wider risk management strategy and ties into contingency planning, where the response to a supplier failure is worked out ahead of time.
The aim is not to remove all dependence, which is neither possible nor desirable, but to know where it exists, decide which of it to accept and have a sensible plan for the rest.