Single source and sole source
Single-source · Sole-source
Single sourcing is a deliberate choice to use one supplier despite alternatives being available, while sole sourcing means no reasonable alternative supplier exists for the requirement.
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Simply put
What it means in ordinary work
One is a choice, the other is a constraint. The distinction matters because the justification, controls and approval route should differ.
Why it matters
Conflating the two can hide weak competition planning or overstate the lack of alternatives. Clear definitions support better challenge and risk management.
A hypothetical in practice
A hypothetical buyer chooses one systems integrator to simplify accountability, even though others could bid. That is single sourcing. A separately approved sole-source case covers a patented component with no substitute.
Common pitfalls
A difficult market is not automatically a sole source. Test whether the requirement, timing or specification can be changed.
Long-term single sourcing can create dependency and reduce future leverage. Plan periodic market tests and exit options.
Regional lens
How this lands where you work
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As-of date for date-sensitive regional content: 5 November 2026. Read the review policy.