A permissive counterclaim is any counterclaim a defendant brings against the plaintiff that isn’t compulsory under Federal Rule of Civil Procedure 13(a). In plain terms, it’s usually a dispute unrelated to the plaintiff’s lawsuit that the defendant chooses to fold in rather than file separately. You can raise it now, or you can skip it and sue later. The catch is that in federal court the claim needs its own jurisdictional footing, and waiting too long can run you into the statute of limitations.1Legal Information Institute. Federal Rules of Civil Procedure Rule 13 – Counterclaim and Crossclaim
What Rule 13(b) Actually Says
Rule 13(b) defines a permissive counterclaim as “any claim that is not compulsory.”1Legal Information Institute. Federal Rules of Civil Procedure Rule 13 – Counterclaim and Crossclaim So the real work is in Rule 13(a). A counterclaim is compulsory when it arises out of the same transaction or occurrence as the plaintiff’s claim and the court can obtain jurisdiction over any additional parties needed to resolve it. Everything else is permissive.
Rule 13(a)(2) carves out two situations where a claim stays permissive even if it shares facts with the plaintiff’s suit: when the claim was already the subject of another pending action, or when the plaintiff started the case through a method such as attachment that did not establish personal jurisdiction over the defendant.1Legal Information Institute. Federal Rules of Civil Procedure Rule 13 – Counterclaim and Crossclaim
Those edge cases aside, most permissive counterclaims are ordinary unrelated disputes between the same two people. A breach of contract suit between two parties who also have an unrelated property damage dispute is the standard example. Different facts, different evidence, different legal theories. Nothing requires the defendant to raise the property damage claim in the contract case.
Telling a Permissive Counterclaim From a Compulsory One
The working test is whether the two claims share a common nucleus of operative facts. If the same witnesses would testify, the same documents matter, and the same timeline runs through both, the counterclaim is almost certainly compulsory. If the evidence barely overlaps, it is permissive.
Judges look at whether resolving the claims separately would duplicate the court’s work, whether the legal issues overlap or sit in entirely different bodies of law, and whether one outcome could logically affect the other. A missed loan payment and a car accident between the same two people involve wholly separate evidence, so the car accident claim would be permissive in the loan suit.
Why the classification matters: a compulsory counterclaim that goes unfiled is waived forever. The defendant cannot bring it in a later lawsuit.1Legal Information Institute. Federal Rules of Civil Procedure Rule 13 – Counterclaim and Crossclaim A permissive counterclaim carries no such penalty. Skip it, and you can file it as its own case later, subject to the statute of limitations. In close cases, many defendants file the counterclaim anyway just to be safe.
Independent Jurisdiction Is Required
This is where permissive counterclaims trip people up in federal court. A permissive counterclaim needs its own basis for subject matter jurisdiction. It cannot ride on the jurisdiction that already supports the plaintiff’s case.
The reason is the supplemental jurisdiction statute, 28 U.S.C. § 1367. It extends federal jurisdiction only to claims “so related” to those already in the action that they form part of the same case or controversy.2Office of the Law Revision Counsel. 28 U.S.C. 1367 – Supplemental Jurisdiction Because a permissive counterclaim typically involves different facts from the plaintiff’s claim, it usually fails that test.
Two paths exist for independent jurisdiction. Federal question jurisdiction under 28 U.S.C. § 1331 applies when the claim arises under the Constitution, federal statutes, or treaties, with no minimum dollar amount.3Office of the Law Revision Counsel. 28 U.S.C. 1331 – Federal Question Diversity jurisdiction under 28 U.S.C. § 1332 requires that the parties be citizens of different states and that the amount in controversy exceed $75,000.4Office of the Law Revision Counsel. 28 U.S.C. 1332 – Diversity of Citizenship; Amount in Controversy; Costs
If your counterclaim meets neither standard, the court will dismiss it and you will have to file in a court that has jurisdiction, typically a state court. This hurdle is the single biggest reason defendants sometimes choose to save a permissive claim for a separate case.
How to File One
The usual vehicle is your Answer to the plaintiff’s complaint. Your defenses go in first, then a section setting out your own claims. If you realize you have a permissive counterclaim after the deadline for the Answer has passed, you need the opposing party’s written consent or the court’s permission to amend under Rule 15.5Legal Information Institute. Federal Rules of Civil Procedure Rule 15 – Amended and Supplemental Pleadings
Judges weigh how far along the case is, whether the plaintiff would be unfairly prejudiced, and whether you had a good reason for the delay. A request made early is far likelier to succeed than one made on the eve of trial.
Any pleading filed after the complaint, including a counterclaim, has to be served on every party under Rule 5. If the plaintiff has an attorney, service goes to the attorney. Hand delivery, mail to the last known address, and electronic filing through the court’s system are all acceptable.6Legal Information Institute. Federal Rules of Civil Procedure Rule 5 – Serving and Filing Pleadings and Other Papers If your counterclaim brings in a new party, that party must be formally served under Rule 4.
Once served, the plaintiff has 21 days to respond to the counterclaim.7United States Courts. Federal Rules of Civil Procedure A plaintiff who ignores it entirely risks a default under Rule 55.8Legal Information Institute. Federal Rules of Civil Procedure Rule 55 – Default; Default Judgment
The Court May Try It Separately
Filing a permissive counterclaim doesn’t mean it gets tried alongside the main case. Under Rule 42(b), judges have broad discretion to order separate trials when doing so serves convenience, avoids prejudice, or saves time.9Legal Information Institute. Federal Rules of Civil Procedure Rule 42 – Consolidation; Separate Trials
Jury confusion is the usual trigger. When a counterclaim involves facts completely unrelated to the plaintiff’s case, mixing both in front of one jury can muddy the issues. Severance doesn’t kill the claim. The court keeps it on the docket for a separate trial, or sends it elsewhere if jurisdiction requires it. The practical result is you end up litigating two cases anyway, which eats into the efficiency rationale for filing in the first place.
Bringing in Additional Parties
If your counterclaim reaches someone who isn’t already in the lawsuit, Rule 13(h) lets you join them by following the joinder rules in Rules 19 and 20.1Legal Information Institute. Federal Rules of Civil Procedure Rule 13 – Counterclaim and Crossclaim Under Rule 20, you can join a new party when your claim against them arises out of the same events as your counterclaim and shares at least one common question of law or fact.10Legal Information Institute. Federal Rules of Civil Procedure Rule 20 – Permissive Joinder of Parties For joinder purposes, you are treated as the plaintiff and the new party as the defendant. The same jurisdictional rules apply to that added claim, and the new party has to be formally served under Rule 4.
Don’t Let the Statute of Limitations Run
The flexibility of permissive counterclaims is a trap for the patient. Because you aren’t required to file now, you might think you have time. But every claim has a deadline, and the clock keeps running even while you are already in a lawsuit with the same person. If the statute of limitations expires while you wait, the claim is gone.
Whether an amended Answer adding a counterclaim “relates back” to an earlier date under Rule 15(c) is unsettled. Some courts allow it, others don’t. The safe assumption is that the limitations period runs independently, so file before it expires, either as a counterclaim or as a separate suit.
Should You File It Now or Later?
This is a tactical decision, not a legal requirement, and the factors cut both ways.
Filing now can shift settlement leverage. The plaintiff is no longer the only one with something to win or lose. Bundling claims can also save the cost of a second lawsuit when you count filing fees, duplicative discovery, and attorney time.
Waiting has its own case. Combining unrelated claims can distract from your defense of the plaintiff’s suit and confuse a jury. The current court may not be the most favorable venue for your unrelated claim, and filing separately lets you choose where to sue. And if your counterclaim cannot clear the independent jurisdiction bar, filing it in the current federal case was never a real option; a separate state court action was always the plan. Figuring that out early saves the wasted effort of drafting a counterclaim the court cannot hear.