Acquisitions exceeding $3000 and not exceeding $100,000 are reserved exclusively for small business and shall be set-aside (see FAR 19 for procedures and exceptions)
Soliciting from a single source:
For actions below the Simplified Acquisition Threshold – contracting officers must document their determination that the circumstances of the contract deem only one source reasonably available
For actions under the Commercial Item Test Program (FAR 13.5) – contracting officers must prepare a sole source justification using the format at 6.303-2 and obtain approval in accordance with the thresholds established at 13.501