Rule 3.401.Complex case designation

Division 4. Parties and Actions · Chapter 5. Complex Cases · Last amended 2007 · Last verified July 29, 2026

In one sentenceRule 3.401 lets a plaintiff designate an action as a complex case by marking the Civil Case Cover Sheet, form CM-010, to indicate complex status and filing and serving it together with the initial complaint.

Full Text of Rule 3.401

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A plaintiff may designate an action as a complex case by filing and serving with the initial complaint the Civil Case Cover Sheet (form CM-010) marked to indicate that the action is a complex case.

Plain-English Summary

Complex-case status does not require a separate motion or a hearing to get started. Rule 3.401 lets the plaintiff make the call at the very outset of the case, by marking the Civil Case Cover Sheet, form CM-010, to show the action is complex, and filing and serving that marked cover sheet along with the initial complaint.

That single act does not settle the question for good — it only starts the case down the complex track and puts the defendant on notice, since rule 3.220 requires the cover sheet to be served whenever it marks a case complex. What follows is a check on the plaintiff's choice: rule 3.402 lets a defendant counterdesignate, and rule 3.403 gives the court its own authority to decide, with or without a hearing, whether the case really belongs on the complex docket defined in rule 3.400.

Frequently Asked Questions

How does a plaintiff designate a case as complex in California?

Under Rule 3.401, the plaintiff marks the Civil Case Cover Sheet, form CM-010, to indicate the action is a complex case, and files and serves it with the initial complaint.

Does designating a case complex under Rule 3.401 mean the court has to treat it that way?

No. The designation starts the process, but rule 3.402 lets a defendant counterdesignate and rule 3.403 gives the court authority to decide the question itself.

When does the complex case designation have to be made?

It has to happen at the outset, since Rule 3.401 requires the marked cover sheet to be filed and served together with the initial complaint.

Amendment History

Rule 3.401 renumbered effective January 1, 2007; adopted as rule 1810 effective January 1, 2000; previously amended effective July 1, 2002, and July 1, 2004.

Source & verification. Rule text is reproduced verbatim from the Judicial Council of California. Adopted by the Judicial Council of California. Last verified July 29, 2026. · Official source

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