Single sourcing in technical purchasing: when dependence on one supplier is worth it

What is meant by single sourcing?

In procurement, single sourcing refers to the strategy of obtaining a specific product, an assembly, a raw material, or a service exclusively from a single supplier, although in principle several providers would be available on the market. This distinguishes single sourcing from so-called sole sourcing, in which there simply is no alternative provider, for example because a supplier holds a patent or has a unique technological position. While sole sourcing thus describes a forced situation, single sourcing is the result of a deliberate business decision.

In technical procurement, single sourcing often concerns specific components with a high degree of specialization, such as custom-manufactured parts, tools with high investment costs, or systems in which a change of supplier would involve considerable requalification effort. The decision in favor of a single supplier can be both strategically intended and historically developed, for example when a supplier has built up exclusive trust over years.

What advantages does single sourcing offer in technical procurement?

Concentrating on one supplier brings several tangible advantages for technical buyers, which in many cases at least partially outweigh the perceived risks.

A key advantage lies in the economies of scale: Anyone who consolidates their entire order volume with one supplier can generally negotiate better purchasing conditions, discounts, and payment terms than would be possible with split volumes across several providers. In addition, there is significantly lower administrative complexity, since fewer supplier relationships have to be maintained, fewer contracts have to be managed, and fewer quality audits have to be carried out.

Technical collaboration also often benefits from single sourcing. A close, long-term partnership facilitates joint development projects, as the supplier builds up deep process knowledge about the buyer's specific requirements. This accelerates innovation cycles and reduces friction losses at the interface between design and manufacturing. Not least, a reduced supplier base also lowers the effort required for quality assurance and certification processes, which enables noticeable efficiency gains, particularly in regulated industries such as the automotive, medical technology, or aerospace industry.

What risks does dependence on a single supplier entail?

The advantages are offset by considerable risks that technical buyers must carefully weigh as part of their sourcing strategy. The greatest risk is security of supply: If the only supplier fails, for example due to insolvency, a fire at the plant, a natural disaster, or geopolitical upheavals, the entire production chain comes to a standstill, without the possibility of switching to an alternative source at short notice. The coronavirus pandemic and the semiconductor crisis have vividly brought this vulnerability to mind.

In addition, single sourcing significantly reduces the buyer's negotiating power. Without a credible fallback option, the pressure on the supplier to make concessions in price negotiations, delivery dates, or quality issues decreases. Over time, this can be reflected in rising prices or declining service quality. The innovation risk should also not be underestimated: A supplier without competitive pressure may have less incentive to invest in new technologies or process improvements.

Finally, a structural concentration risk arises that can have serious financial and reputational consequences, particularly for critical, safety-relevant, or high-revenue products, should the supply chain be interrupted.

In which cases is single sourcing still sensible?

Despite the risks mentioned, there are constellations in which single sourcing represents an economically and strategically viable decision. 

This includes, in particular, situations in which the complexity or specificity of a component makes a broad supplier base impractical anyway, for example in the case of highly specialized tools, customer-specific custom-made products, or components with a very low procurement volume, for which maintaining several supplier relationships is not economically worthwhile.

Single sourcing can also be the right path in strategic partnerships in which joint development investments, shared intellectual property, or exclusive access to technology are the focus. The strategy is also suitable when the supplier has demonstrably shown high delivery reliability, stable quality, and financial solidity over many years and the procured product does not perform a safety-critical function in the end product.

What is decisive in every case is a differentiated assessment according to criticality: For non-critical components with low risk and a low share of value, single sourcing is often the most economical solution, while a broader setup is advisable for strategically important or supply-critical parts.

How does single sourcing differ from dual and multi sourcing?

In a company's sourcing portfolio, purchasers generally have three basic strategies available to them, which differ significantly in risk profile, cost structure, and control effort.

Single sourcing: Procurement from exactly one supplier, maximum bundling, highest dependency risk.

Dual sourcing: Procurement from two suppliers, often with a fixed quantity split, balanced relationship between risk diversification and favorable terms.

Multi sourcing: Procurement from three or more suppliers, highest security of supply, but higher coordination and quality assurance effort as well as lower economies of scale per supplier.

The choice of the appropriate strategy depends substantially on the degree of criticality of the product, the market availability of alternative providers, and the strategic importance of the supplier relationship. In practice, many companies pursue a segmented approach in which different sourcing strategies are applied in parallel for different product categories.

How can the risk of single sourcing be safeguarded in practice?

Anyone who deliberately chooses single sourcing should not do so without safeguards, but should take accompanying measures to reduce vulnerability. A central instrument is contractual protection, for example through binding delivery commitments, contractual penalties in the event of delivery failure, minimum inventory agreements at the supplier, or the definition of escalation mechanisms for crisis situations.

In addition, it is advisable to build up strategic safety stocks for particularly critical components in order to be able to bridge short-term supply interruptions without immediately jeopardizing production. A so-called second-source qualification, in which an alternative supplier is not actively supplying but is already technically approved and qualified for emergencies, also significantly reduces response time in a crisis without giving up the ongoing cost advantages of single sourcing.

In addition, continuous supplier risk management is essential. This includes regular credit checks, on-site audits, the assessment of the supplier's dependence on its own upstream suppliers, as well as systematic monitoring of geopolitical and macroeconomic developments that could affect supply capability.

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What role does single sourcing play for innovation partnerships?

In addition to the pure consideration of risk, single sourcing also has a strategic dimension that is becoming increasingly important in technical procurement. When a company develops new technologies together with a supplier, both sides benefit from close, exclusive collaboration. The supplier gains planning security for its investments, while the buyer gains early access to innovations and customized solutions that would hardly be realizable in a broadly diversified supplier portfolio.

This form of strategic partnership, however, requires a high degree of mutual trust, clearly regulated intellectual property, and an open communication culture. In such constellations, technical buyers should pay particular attention to contractual provisions on exclusivity, intellectual property rights, and exit scenarios in order to remain capable of acting even in the event of a later change in strategy.

What significance does single sourcing have in light of geopolitical risks?

At the latest since the coronavirus pandemic, the war in Ukraine, the tensions between China and the USA, as well as increasing trade conflicts, the assessment of single sourcing has changed fundamentally. Supply chains are now no longer regarded exclusively as a cost factor, but as a strategic competitive advantage.

Technical buyers therefore no longer look only at the individual supplier, but at the entire supplier network. Decisive factors include, among other things, where production takes place, which upstream suppliers are involved, and how strongly individual regions are affected by political risks, export restrictions, or natural disasters.

Single sourcing therefore does not necessarily mean a higher risk today. If, for example, the supplier is located in Europe, has several production sites, and a stable supply chain, security of supply can be higher than with several suppliers with identical upstream suppliers in the same region.

For this reason, a regular analysis of geopolitical risks is now part of professional supplier management.

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Why should single sourcing be evaluated based on total cost of ownership?

The decision in favor of single sourcing should not be made exclusively on the basis of the purchase price. Much more meaningful is consideration of the total cost of ownership (TCO) , that is, all costs over the entire life cycle of a procurement.

In addition to the part price, the following factors, among others, are included:

• Logistics and transportation costs
• Storage costs
• Quality costs
• Complaints
• Audit and supplier management
• Tooling and start-up costs
• Process costs in purchasing
• Costs of a possible supplier change

Especially in technical purchasing, it is often evident that a supposedly low-cost supplier causes higher total costs across the entire value chain than a high-performing strategic partner. Single sourcing can therefore be more economical despite slightly higher unit prices if process costs and quality effort decrease significantly.

What role do digital tools play in single sourcing?

Modern SRM systems (Supplier Relationship Management), digital supplier platforms, and AI-supported risk management solutions are significantly changing the handling of single sourcing. Today, numerous risks can be continuously monitored, for example:

• a supplier's financial stability
• delivery performance
• quality metrics
• ESG risks
• cybersecurity
• political developments
• weather and natural disasters
• transport disruptions

As a result, companies recognize potential problems much earlier and can initiate countermeasures before delivery failures occur. Artificial intelligence in particular is gaining importance here by analyzing large volumes of data from different sources and automatically identifying risk trends.

In which industries is single sourcing particularly widespread?

Single sourcing is found primarily in industries with high quality and approval requirements. These include, for example, the automotive industry, aerospace, medical technology, mechanical and plant engineering, the semiconductor industry, energy technology, and rail technology.

What these industries have in common is that suppliers often have specialized process know-how, certified manufacturing processes, or long-standing development partnerships. Accordingly, changing suppliers would be time-consuming and cost-intensive.

Typical examples of single sourcing are: special tools with customer-specific geometry, patent-protected sensors, proprietary control systems, specialized bearings, customer-specific cast parts, individually developed electronics, software solutions with exclusive interfaces.

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How should technical buyers make the decision for single sourcing in a structured way?

A well-founded decision for or against single sourcing should not be made intuitively, but on the basis of a systematic evaluation. A proven approach is to classify the components to be procured according to criticality and procurement risk, as is done, for example, within the framework of the Kraljic matrix. Components with high supply risk and high strategic importance should generally be critically examined for their suitability for single sourcing, while non-critical standard parts with a low value share can often be sourced without problems from a single supplier.

A structured checklist ensures comprehensible decisions and facilitates documentation vis-à-vis management, auditors, and customers:

• Are there technically equivalent alternative suppliers?
• How high would the effort for requalification be?
• How critical is the component for production?
• How high is the financial risk of a supply failure?
• Is the supplier financially stable?
• Does it have multiple production sites?
• How transparent is its supply chain?
• Are emergency and escalation plans in place?
• Does a qualified second source already exist?
• Do the process and innovation advantages outweigh the dependency risks?

Only the overall view of these factors enables a robust, comprehensible sourcing decision that also stands up vis-à-vis internal stakeholders and in the context of supply chain audits.