What Is Rule 408? Compromise Offers, Exceptions, and Rule 409

Federal Rule of Evidence 408 blocks parties from using settlement offers, or statements made during settlement negotiations, as evidence at trial to prove whether a disputed claim is valid or how much it is worth. The rule exists so litigants can talk honestly at the bargaining table without fearing their words will be replayed in front of a jury. Its protection is broad, but it has defined edges, and understanding both the shield and the gaps matters whenever a civil dispute could end up in court.¹

What the Rule Keeps Out

Rule 408 excludes two categories of evidence when offered to prove or disprove the validity or amount of a disputed claim.

The first is the compromise itself: offering, promising, or accepting something of value to settle a contested claim. If a defendant offers $50,000 to resolve a $100,000 lawsuit, neither side can later point to that offer as proof the defendant believed it was liable or that the plaintiff’s case was only worth half of what was demanded.¹

The second category is wider and tends to matter more in practice: any statement or conduct made during compromise negotiations about the claim. Admissions of fault, concessions on specific facts, floated damages numbers — all generally inadmissible. The point is to let both sides speak freely. If every concession could resurface at trial, no one would make one, and negotiations would become performance.¹

The protection runs both ways. The rule’s text says evidence is inadmissible “on behalf of any party.” A plaintiff cannot introduce the defendant’s offer to show guilt, and a defendant cannot introduce the plaintiff’s willingness to accept a low number to argue the claim was weak. The 2006 amendment clarified this symmetry.¹

There Has to Be a Disputed Claim

Rule 408 only applies when the parties genuinely disagree about either the validity of a claim or the amount owed. If someone owes an undisputed invoice and offers to pay part of it, that offer is not protected. The rule is meant to encourage resolution of real disagreements, not to shield negotiation of admitted debts.¹

A lawsuit is the clearest marker of a dispute, but Rule 408 can apply earlier. Once one side sends a demand and the other pushes back on liability or amount, a dispute exists. The House Judiciary Committee acknowledged when the rule was adopted that “it is not always easy to tell when compromise negotiations begin, and informal dealings end.” Casual problem-solving can slide into negotiation without a clear line. Until a dispute is clearly established, assume a communication is not protected.

When Settlement Evidence Can Still Come In

Rule 408 is not a blanket seal. Settlement evidence is admissible when offered for a purpose other than proving or disproving the disputed claim. The rule lists three familiar examples, and courts are not limited to them.¹

Proving witness bias or prejudice. If a witness settled with one party before trial, the other side can bring up the settlement to show a financial motive for favorable testimony. The point is not fault; it is objectivity.
Negating a claim of undue delay. If one side accuses the other of dragging its feet, evidence of active negotiations can rebut that charge.
Proving an effort to obstruct a criminal investigation. Trying to buy off a prosecutor or a cooperating witness falls outside the rule’s protective policy. Rule 408 encourages legitimate compromise, not bribery or witness tampering.

Even when settlement evidence qualifies under a permitted purpose, the court still weighs it. If the risk of unfair prejudice substantially outweighs its value for that purpose, the judge can keep it out. A jury that hears “the defendant offered to settle for $200,000” will struggle to set the number aside when deciding liability.

No Using Settlement Statements for Impeachment

Before 2006, courts split on whether settlement statements could be used to impeach a witness through a prior inconsistent statement. The 2006 amendment resolved it. The current rule flatly prohibits using compromise evidence “to impeach by a prior inconsistent statement or a contradiction.”¹

Without that ban, a lawyer could cross-examine with a line like, “Didn’t you say during settlement talks that you were going 30 miles per hour? Now you’re claiming 20?” That would hollow out the rule. Factual concessions made at the table would become ammunition on cross, and parties would stop making them.

Civil Settlement Talks and Later Criminal Cases

The 2006 amendment drew a sharp line involving the government. When someone negotiates a civil settlement with a government agency exercising regulatory, investigative, or enforcement authority, statements or conduct from those negotiations can be admitted in a later criminal prosecution.¹

The reasoning is that someone sitting across from federal regulators knows the stakes. Admissions made to a government agency during civil settlement talks are available in a later criminal case because the speaker understood they were dealing with the government. The advisory committee notes point out that the individual “can seek to protect against subsequent disclosure through negotiation and agreement with the civil regulator.”¹

Statements made during settlement talks between private parties remain protected even if a criminal case later arises from the same facts. Private litigants cannot negotiate immunity from criminal use of their words, and without reliable protection they would refuse to engage in meaningful discussions.

Even in the government-agency setting, there is a nuance. The fact that someone accepted a settlement is still excluded if offered to show the defendant admitted guilt by settling. An offer to compromise is weak evidence of actual guilt, and allowing it would discourage people from resolving civil regulatory actions. The exception targets direct statements of fault, not the act of settling.

Rule 408 vs. Rule 409

Rule 408 is often confused with Federal Rule of Evidence 409, which covers offers to pay medical or similar expenses. They look alike but differ in a way that catches people out.²

Rule 408 protects the settlement offer and everything said during the negotiations around it. Rule 409 is narrower. It excludes only the offer to pay medical expenses, not any factual statements made alongside it. If a driver says, “I ran the red light; let me pay your hospital bills,” Rule 409 keeps the offer to pay out of evidence but does nothing for the admission about the red light.²

The practical takeaway: if you are offering to cover someone’s medical costs and you want your words protected, the conversation needs to be framed as a settlement negotiation of a disputed claim, not a standalone offer to pay bills.

Common Mistakes

Stamping an email “For Settlement Purposes Only” does not automatically trigger Rule 408. The label can help show you intended the communication as part of compromise negotiations, but the rule’s requirements still have to be met on their own: a disputed claim, a statement made during compromise negotiations, and evidence offered for a prohibited purpose. A court looks at the substance, not the header.

The reverse is also true. A missing settlement label does not kill the protection. If a communication was genuinely part of negotiations over a disputed claim, Rule 408 applies regardless of formatting. The label is evidence of intent, not a legal requirement.

One more trap: Rule 408 is not a discovery privilege. It governs admissibility at trial. Some courts have held that settlement materials are still discoverable even when they would be inadmissible under Rule 408. If you want settlement communications kept out of discovery entirely, you may need other tools, such as mediation confidentiality rules or a court-approved protective order.

1
Legal Information Institute. Federal Rules of Evidence Rule 408 – Compromise Offers and Negotiations
2
Legal Information Institute. Federal Rules of Evidence Rule 409 – Offers to Pay Medical and Similar Expenses