If you’ve been told that cooperation will “definitely” reduce your prison sentence, I encourage you to read this carefully to learn more about a 5k1.1 and rule 35s.

In theory, cooperation is a way to earn a better outcome. In practice, it’s a complicated process that depends entirely on what the government thinks of your value—and when they think it. That’s where two sentencing mechanisms come into play: 5K1.1 and Rule 35(b).

I’ve worked with people who received significant sentence reductions through both. I’ve also seen people cooperate for months or years and receive no benefit at all. To make smart choices, you need to understand how these tools work—and more importantly, how they’re used.

What Is a 5K1.1 Motion?

A 5K1.1 is a formal motion the government can file at sentencing, asking the judge to impose a sentence below the advisory guideline range because the defendant provided “substantial assistance.”

It’s important to understand:

• You can’t request it. Only the U.S. Attorney’s Office can file a 5K1.1 motion.
  
• It’s discretionary. Even if you sat for proffers, testified, or turned over documents, they are under no obligation to ask for a reduction.
  
• It’s timing-dependent. It must be filed before sentencing.
  

If the government files a 5k1.1 the judge will typically reduce the sentence. But by how much? That depends.

While there are no fixed percentages, in white-collar cases I’ve worked on or reviewed, judges often reduce sentences by 25–50%—sometimes more, sometimes less. It’s not a guaranteed formula. Some get 10%. Others walk away with a sentence cut in half. In rare cases, cooperators avoid prison altogether.

Let’s look at a real-world example of a 5k1.1

In the Martin Shkreli case (the “Pharma Bro”), one of his co-conspirators, Evan Greebel, declined to cooperate. He went to trial and was convicted, receiving 18 months in prison. Had he cooperated, based on similar cases, it’s likely the government would have filed a 5K1.1—and he may have avoided prison. That was a strategic choice. Others in similar financial fraud cases who cooperated early—like in the Enron or WorldCom prosecutions—saw significant reductions based on their willingness to assist.

What Is Rule 35(b)?

A Rule 35(b) motion is different. It comes after sentencing.

It’s used when a defendant provides substantial assistance after their sentence has already been imposed. This often happens when someone’s cooperation continues post-sentencing—through trial testimony, new investigations, or providing leads that result in indictments or convictions.

Key facts:

• Again, only the government can file a Rule 35(b).
  
• There’s no deadline, but it typically happens within a year of sentencing.
  
• The court can then reduce the sentence retroactively.
  

Rule 35 motions are less common in white-collar cases, but they do happen—particularly when the government needs extended cooperation. The longer you remain helpful, the more likely they are to use this tool.

But there’s a risk: you’re already sentenced. You may sit in prison for months—or longer—waiting for the government to decide whether you helped enough to earn relief. That uncertainty can be maddening.

What Determines Whether You Get a 5k1.1 Motion?

Here’s what prosecutors look for:

• Credibility. Did you tell the truth? Did your story hold up under scrutiny?
  
• Usefulness. Did your information lead to charges or convictions? Did you testify?
  
• Timing. Did you come forward early—or only after everyone else had flipped?
  
• Attitude. Were you forthcoming, or did you require multiple proffers to get to the truth?
  

Cooperation that’s too little or too late doesn’t carry much weight. Worse, if the government feels you were evasive or misleading—even unintentionally—they may walk away entirely.

That’s what happened with my co-defendant. He agreed to cooperate. He sat for proffers. Then, months later, he was indicted on new charges. That violated the terms of his cooperation and plea agreement. As a result, he never got a 5K1.1. His cooperation became worthless to the government, and he received a longer sentence than he would have if he had never cooperated at all.

Final Thoughts

Cooperation can absolutely work. But it’s a high-risk strategy that depends on how the government sees you—and whether you deliver something they truly need.

If you’re considering cooperation or hoping to earn a 5K1.1 or Rule 35(b), preparation is everything. It’s not enough to be willing. You have to be credible, thorough, and ready to deliver value from the government’s perspective.

If you’re unclear about what cooperation might look like in your case—or whether you’re being promised more than the government can deliver—schedule a call with our team today. We’ve been through it, we’ve guided others through it, and we’ll help you make the most informed decision possible.

Justin Paperny