5K1.1 Explained: The Substantial-Assistance Guideline in Plain Language

What § 5K1.1 Says

USSG § 5K1.1 — Substantial Assistance to Authorities — provides that upon motion of the government stating that the defendant has provided substantial assistance in the investigation or prosecution of another person who has committed an offense, the court may depart from the guidelines.

The guideline then lists factors the court may consider in deciding whether to depart, and how much.

The Five Factors

1. Significance and usefulness of the defendant's assistance, taking into consideration the government's evaluation of the assistance rendered.
2. Truthfulness, completeness, and reliability of any information or testimony provided.
3. Nature and extent of the defendant's assistance.
4. Any injury suffered, or any danger or risk of injury, to the defendant or the defendant's family resulting from the assistance.
5. Timeliness of the defendant's assistance.

What § 5K1.1 Does Not Do

• It does not authorize the court to depart on its own — a government motion is required.
• It does not authorize a sentence below a statutory mandatory minimum. That requires a separate motion under 18 U.S.C. § 3553(e).
• It does not set a fixed reduction. The court has wide discretion.
• It does not apply to assistance that becomes substantial only after sentencing — that is handled under Rule 35(b).

How § 5K1.1 Fits With Other Provisions

• USSG § 5K1.1 — guideline departure for substantial assistance, pre-sentencing.
• 18 U.S.C. § 3553(e) — statutory authority to go below a mandatory minimum, also on government motion for substantial assistance.
• Fed. R. Crim. P. 35(b) — post-sentencing reduction for substantial assistance, on government motion.

Practical Takeaways

• A 5K1 reduction is a court decision based on the government's motion.
• The size of any departure varies case-by-case.
• The reduced sentence is then computed by the BOP using its standard rules — GCT, FSA credits, RDAP, RRC, and home confinement all still apply.