5K1 vs Rule 35(b): Pre-Sentencing and Post-Sentencing Cooperation Explained

Two Motions, Same Goal, Different Timing

Both USSG § 5K1.1 and Fed. R. Crim. P. 35(b) allow a federal court to reduce a sentence when the defendant has provided substantial assistance in the investigation or prosecution of another person. The difference is when the motion is filed and when the reduction takes effect.

5K1.1: Before Sentencing

A 5K1.1 motion is filed by the government before the original sentencing hearing. The court considers the motion and, if it grants the departure, imposes a reduced sentence from the start. The defendant begins serving the already-reduced term.

• Filed: before or at sentencing
• Effect: the sentence imposed by the court is lower from day one
• Standard: substantial assistance to authorities
• Requires: government motion
• Can also support: a motion under 18 U.S.C. § 3553(e) to go below a statutory mandatory minimum

Rule 35(b): After Sentencing

A Rule 35(b) motion is filed by the government after sentencing. The court amends the previously imposed sentence to a lower term. The defendant receives a reduced sentence while already serving time.

• Filed: after sentencing, usually within one year
• Effect: the already-imposed sentence is reduced by court order
• Standard: substantial assistance to authorities
• Requires: government motion
• Time limit: generally one year, with narrow exceptions

Side-by-Side Comparison

Why Timing Changes the Practical Impact

A 5K1.1 reduction is built into the sentence from day one. Good Conduct Time, First Step Act credits, RDAP, and RRC placement are all calculated from the lower number.

A Rule 35(b) reduction arrives after some or all of those mechanisms have already begun running. Depending on when the motion is granted, the defendant may already be close to prerelease custody. The reduction still lowers the sentence on paper, but the actual months saved inside a federal facility may be smaller than the numerical reduction suggests.

For a deeper walk-through of how post-sentencing reductions interact with BOP release planning, see Understanding Rule 35(b) and Federal Release Date Timing.

Can a Defendant Get Both?

Yes. A defendant may receive a 5K1.1 departure at sentencing and, if new substantial assistance emerges later, seek an additional reduction under Rule 35(b). Each motion is independent, requires a separate government filing, and receives its own judicial decision.

Records to Organize

• Judgment and Commitment Order and any amended judgments
• Plea agreement and any cooperation addendum
• Presentence Investigation Report (PSR)
• Sentence Monitoring Computation Data sheets
• Documentation of programming, education, and work assignments
• Any correspondence or filings related to the timing of a Rule 35(b) motion