Single Source vs Sole Source

Sole Source vs Single Source: Side-by-Side Comparison

Factor	Sole Source	Single Source
Vendor availability	Only one vendor exists	Multiple vendors exist, one selected
Reason for no competition	No alternatives available	Strategic choice by the agency
Common justifications	Proprietary technology, patent, unique expertise	Compatibility, transition costs, prior experience
FAR authority	FAR 6.302-1 (only one responsible source)	May use various FAR exceptions
Scrutiny level	High — requires J&A documentation	High — also requires justification
Protest risk	Lower (hard to argue alternatives exist)	Higher (competitors may challenge the selection)

Examples

Sole source example: An agency needs maintenance on a weapons system built by Lockheed Martin. Only Lockheed has the proprietary technical data and tooling. No other vendor can perform the work — this is a true sole source.

Single source example: An agency has used Cisco networking equipment for 10 years. Multiple vendors sell comparable switches (Juniper, Arista), but switching would require retraining staff and reconfiguring the entire network. The agency single-sources to Cisco for compatibility and transition cost reasons.

Why This Matters for Contractors

If you're the sole source, your negotiating position is strong but you still need to demonstrate fair pricing. If you're being single-sourced, be aware that competitors can protest the award — the agency needs solid justification. In both cases, having a sole source justification on file strengthens the award's defensibility.

Small businesses with 8(a), SDVOSB, or HUBZone certifications can receive sole-source awards up to statutory thresholds without competing — making these certifications powerful tools for winning non-competitive work.