What Is an MDL? Multidistrict Litigation Explained

By Steve Levine · Updated July 2, 2026 · 8 min read

Quick Answer

Multidistrict litigation (MDL) is a federal procedure under 28 U.S.C. § 1407 that gathers similar lawsuits filed all over the country — usually against the same defendant over the same product or conduct — in front of a single judge for coordinated pretrial work. Unlike a class action, every MDL plaintiff keeps their own individual lawsuit with their own facts and damages; the MDL just keeps thousands of cases moving together through discovery and test ("bellwether") trials, which typically pressure the parties toward a global settlement.

On this page

What Is an MDL?
How an MDL Works, Step by Step
MDL vs. Class Action
What an MDL Means for You as a Claimant
Active MDLs We're Tracking
MDLs That Produced Settlements
Frequently Asked Questions

What Is an MDL?

When the same product or corporate conduct injures people in many states — a recalled drug, a defective medical device, a massive data breach, an addictive app design — federal courts can end up with hundreds or thousands of nearly identical lawsuits. Multidistrict litigation is the system Congress created in 1968 to handle that. A seven-judge body called the Judicial Panel on Multidistrict Litigation (JPML) decides whether the cases share enough common questions to be centralized, and if so, it transfers them all to one "transferee" judge in one federal district.

The point is efficiency and consistency: one judge rules on the shared scientific and corporate-knowledge evidence once, instead of hundreds of judges ruling on the same documents in conflicting ways. Each lawsuit inside the MDL remains a separate case, owned by its own plaintiff. MDLs now make up a large share of the entire federal civil docket, and the biggest ones — like the social media addiction and Roblox child-safety litigations covered below — contain hundreds or thousands of individual suits.

How an MDL Works, Step by Step

1. Petition and centralization. A party asks the JPML to consolidate the scattered cases. If granted, the JPML assigns an MDL number (e.g. MDL 3047) and picks the transferee court and judge.

2. Leadership and master complaints. The judge appoints lead plaintiffs' counsel and a steering committee, and the parties typically file consolidated "master" pleadings so common legal issues can be decided once.

3. Coordinated discovery. Document production, depositions of company witnesses, and expert reports happen once for the whole MDL. Plaintiffs usually complete fact sheets describing their individual injuries.

4. Bellwether trials. A handful of representative cases are tried first. The verdicts aren't binding on anyone else, but they tell both sides what juries think the claims are worth.

5. Global settlement or remand. Most large MDLs end in a negotiated settlement program that scores each case on injury severity. Recoveries are typically subject to a court-ordered common benefit fee that compensates leadership counsel. Cases that don't resolve are remanded — sent back to their original districts for individual trials.

MDL vs. Class Action

The two get confused constantly, including by news coverage. A class action is one lawsuit on behalf of everyone with the same (usually smaller, uniform) loss — think overdraft fees or a data breach — and class members typically just file a claim form when a settlement opens, or opt out if they want to sue alone. An MDL is a bundle of individual lawsuits — the classic mass tort posture — used when injuries are too personal and too different for one class — cancers, assaults, device failures — so each plaintiff needs their own case and their own damages number.

Practical differences that matter to consumers: an MDL has no claim form and no "automatic" membership — if you don't file a suit, you're not in it. Payouts aren't pro rata splits of a single fund; settlement matrices grade each injury. And statutes of limitations run individually, so waiting too long can extinguish your claim even while the MDL is active. (The two systems can also coexist: a class action over economic loss can run alongside an MDL over physical injuries from the same product.)

What an MDL Means for You as a Claimant

If you were harmed by a product or platform that's in an active MDL, the path is: speak to an attorney who handles that litigation (virtually all work on contingency), confirm your facts fit the case criteria, and file your individual suit so it's transferred into the MDL. From there your case rides along with the coordinated proceedings. If a global settlement arrives, you'll be offered a graded award based on your injuries; if not, your case can be tried. Be wary of anything that looks like a "sign-up form" promising MDL money — legitimate MDLs pay only people who actually filed cases (or, occasionally, registered claims under a court-supervised settlement program).

Active MDLs We're Tracking

These multidistrict litigations are active and covered on OpenClassActions, with eligibility details on each page:

MDL 3047Social Media Addiction Lawsuit (Instagram, TikTok, Snapchat, YouTube, Facebook) — youth mental-health harm from addictive platform design, N.D. Cal.
MDL 3166Roblox Child Predator Lawsuit — child sexual exploitation and grooming claims against Roblox Corporation, N.D. Cal.
MDL 3081Bard PowerPort Lawsuit — implanted port catheter fracture and infection injuries.

MDLs That Produced Settlements

For a sense of where MDLs end up, these consolidated litigations covered on OCA reached settlement programs:

MDL 2406Blue Cross Blue Shield Antitrust Settlement — $2.67 billion subscriber fund, payments distributed.
MDL 2924Zantac (Ranitidine) Settlement — cancer claims over NDMA contamination.
MDL 2875Valsartan, Losartan & Irbesartan Settlement — contaminated blood-pressure drug refunds.

Frequently Asked Questions

Is an MDL the same as a class action?

No. In a class action, one lawsuit covers everyone in the class and most members do nothing until a settlement claim window opens. In an MDL, every plaintiff files their own individual lawsuit; the cases are only grouped before one judge for pretrial proceedings, and each case keeps its own facts, damages, and outcome.

How do I join an MDL?

You don't sign up or file a claim form. You join by filing your own lawsuit, usually through an attorney who handles that litigation. If your case is filed in (or transferred to) federal court, it is routed to the MDL automatically. Most MDL attorneys work on contingency, meaning no fee unless you recover.

What is a bellwether trial?

A bellwether is an early test trial of a small number of representative cases in the MDL. The verdicts are not binding on other plaintiffs, but they show both sides how juries value the claims, which often drives a global settlement for the remaining cases.

How much do MDL plaintiffs receive?

There is no single fund split evenly. If an MDL produces a global settlement, payments are usually set by a points or tier matrix based on the severity of each plaintiff's injury, so individual recoveries in the same MDL can range from a few thousand dollars to millions.

How long does an MDL take?

Typically years. Consolidation, coordinated discovery, and bellwether trials commonly take two to five years before global settlement talks mature, and some MDLs run far longer. Cases that don't settle are sent back to their original courts for trial.