How to Start a Class Action Lawsuit
Thinking of starting a class action? Learn when it makes sense, how to become the lead plaintiff, the steps to file, and what it costs (usually nothing up front).
Starting a class action lawsuit lets one person sue on behalf of hundreds — or millions — of people harmed the same way. This guide explains when it makes sense, how to become the lead plaintiff, the exact steps to file, and what it costs (usually nothing up front).
What Is a Class Action Lawsuit?
A class action lawsuit is a single legal case where one or more named plaintiffs sue a defendant on behalf of a larger group of people with the same legal claim. The group is called the "class," and each member is a class member.
Class actions are most common in consumer fraud, defective products, data breaches, employment violations, and securities fraud. They let people pool their claims when no single person's loss is large enough to justify suing alone.
Browse open class actions to see active cases you may already qualify for without starting anything new.
When Does a Class Action Make Sense?
A class action makes sense when many people suffered the same harm from the same defendant and individual lawsuits would be too costly to pursue. The key test is whether the facts and legal questions are the same across the whole group.
Common situations include a company charging hidden fees to thousands of customers, a data breach exposing millions of records, or a drug causing the same side effect in a large patient population. In 2023, U.S. federal courts saw over 8,000 class action filings — the majority involving consumer protection and labor claims.
A class action is usually the wrong path when your harm is unique, when you need specific relief tailored to your situation, or when your individual damages are very large. In those cases, an individual suit gives you more control.
What Are the Legal Requirements?
Federal Rule of Civil Procedure 23 sets four mandatory requirements — called the Rule 23(a) factors — that every class action must satisfy before a court will certify the class.
The Four Rule 23(a) Requirements
| Requirement | What It Means | Common Threshold |
|---|---|---|
| Numerosity | The class is too large to join all members individually | Usually 40+ members minimum |
| Commonality | There are common questions of law or fact across the class | At least one shared legal issue |
| Typicality | The lead plaintiff's claims are typical of the class claims | Same harm, same defendant conduct |
| Adequacy | The lead plaintiff and attorneys will fairly represent the class | No conflicts of interest |
Beyond these four, the case must also fit one of the Rule 23(b) categories. Most consumer class actions fall under Rule 23(b)(3), which requires that common questions predominate and that a class action is the superior method of resolving the dispute. You can read the full rule text on the federal courts rules page.
How to Become the Lead Plaintiff
The lead plaintiff — also called the named plaintiff or class representative — is the person whose name appears on the lawsuit and who speaks for the entire class throughout the case. Becoming the lead plaintiff is the most direct way to start a class action from scratch.
What the Lead Plaintiff Does
The lead plaintiff works closely with the attorneys, provides documents and records, sits for depositions, and must be available throughout the litigation. This can span several years. The lead plaintiff typically receives a modest additional payment at settlement called an incentive award, which courts in 2024 approved at a median of around $5,000 to $15,000.
Who Qualifies as Lead Plaintiff
You should have clear, documented harm from the defendant's conduct. Your situation must be a good fit for the class — meaning your facts mirror what most other class members experienced. Courts will reject a lead plaintiff whose claim is too unique or who has a personal conflict with the defendant.
In securities class actions, the lead plaintiff is typically the investor with the largest financial loss. Under the Private Securities Litigation Reform Act (PSLRA), that person has a presumption of appointment. See the SEC's class action resources for details on securities-specific rules.
How to Find a Class Action Attorney
Finding the right class action attorney is the single most important step in starting a class action. Class action law is complex, and only firms with experience in mass litigation can realistically take a case from filing to settlement or trial.
What to Look For
Look for a plaintiffs' firm with a track record in the specific type of case you have — consumer fraud, employment, data privacy, or product liability. Ask how many class actions the firm has certified and settled. A good firm will evaluate your case for free.
Most class action attorneys work entirely on contingency. They charge nothing unless the case settles or goes to verdict. The attorney fee — typically 25% to 33% of the total recovery — comes out of the settlement fund, not your pocket.
Red Flags to Avoid
Avoid any attorney who asks for upfront retainer fees in a class action. Avoid firms that cannot name past class action verdicts or settlements. Be skeptical of anyone who guarantees a specific outcome before reviewing the facts.
Step-by-Step: How to File a Class Action
Filing a class action follows a predictable sequence, but each step requires attorney involvement. Here is what the process looks like from the beginning.
Step 1 — Document Your Harm
Gather everything that proves the defendant's conduct harmed you: receipts, contracts, screenshots, medical records, pay stubs, communications. The stronger your documentation, the stronger your case as a lead plaintiff candidate.
Step 2 — Contact a Class Action Attorney
Submit your information to a plaintiffs' firm for a free case review. The attorney will assess whether your claim has the elements needed for class certification. This is also when you discuss whether a class action already exists that you could join instead of starting a new one.
Step 3 — File the Complaint
The attorney drafts and files a complaint in the appropriate federal or state court. The complaint names the lead plaintiff, describes the class, states the legal claims, and requests class certification. For a general overview of this stage, see how to file a lawsuit.
Step 4 — Serve the Defendant
The defendant is formally served with the complaint. The defendant then has time — typically 21 days in federal court — to respond, either with an answer or a motion to dismiss.
Step 5 — Discovery
Both sides exchange documents, take depositions, and gather evidence. Discovery in class actions is typically broader and more expensive than in individual cases because it must cover the entire class period and all affected members.
Step 6 — Motion for Class Certification
Your attorneys file a motion asking the court to formally certify the class. This is the most critical hearing in a class action. The judge evaluates all four Rule 23(a) factors and the applicable Rule 23(b) category. Most class actions that survive certification will ultimately settle.
Step 7 — Settlement or Trial
The vast majority — roughly 90% — of certified class actions settle before trial. If the case settles, the court must approve the settlement as fair, reasonable, and adequate. Class members receive notice and have the right to object or opt out.
What Does It Cost to Start a Class Action?
Starting a class action costs nothing out of pocket for the lead plaintiff in virtually every consumer, employment, and product liability case. Attorneys take these cases on a pure contingency fee basis because the potential class-wide recovery justifies the investment.
The firm advances all litigation costs — filing fees, expert witnesses, depositions, travel, and document review. These costs are reimbursed from the settlement fund. If the case loses, the firm absorbs the loss, not you.
The contingency fee percentage is set in the retainer agreement and is typically between 25% and 33% of the gross recovery. Courts review and must approve the fee at settlement. In federal class actions, judges have reduced excessive fee requests — so the system has a built-in check.
Class Action vs. Individual Lawsuit
A class action consolidates many similar claims into one case, while an individual lawsuit is filed by one plaintiff for their own damages alone. The right choice depends on the size of your individual loss and the nature of the defendant's conduct.
| Factor | Class Action | Individual Lawsuit |
|---|---|---|
| Best for | Small individual losses, widespread harm | Large unique losses, personal injury |
| Cost to plaintiff | Usually $0 up front | Varies; contingency or hourly |
| Control over outcome | Limited — class decides collectively | Full — you make all decisions |
| Individual recovery | Often small (share of total fund) | Full individual damages |
| Time to resolution | 2–5 years typical | 1–3 years typical |
| Defendant deterrence | High — class-wide liability | Lower — limited exposure |
If you suffered a small loss — say, $50 in overcharges — an individual lawsuit is not practical. A class action is the only realistic way to get any recovery. If you lost $500,000 in a fraud scheme, an individual suit often makes more sense. Use our eligibility check tool to get an instant read on which path fits your situation.
How Long Does a Class Action Take?
Most class actions take two to five years from filing to final settlement distribution. Complex pharmaceutical or securities cases can take seven to ten years. Consumer cases with strong facts and cooperative defendants sometimes resolve in eighteen to twenty-four months.
Typical Milestones
Filing the complaint takes weeks. Surviving a motion to dismiss takes six to twelve months. Completing discovery and briefing class certification takes another one to two years. Settlement negotiation, court approval, and distribution add another six to eighteen months on top of that.
The clock does not run evenly. Cases accelerate during motion practice and depositions, then slow during court scheduling delays. Your attorney should give you a realistic timeline estimate based on the specific judge and jurisdiction.
What Happens After You File?
After filing, the case enters a holding pattern while both sides prepare for the class certification battle. This is when the defendant's strategy usually becomes clear — either aggressive motion practice to kill the case early, or early settlement signals to avoid the cost of litigation.
As lead plaintiff, you will be asked to produce documents, sit for a deposition, and review key filings. Your attorneys handle everything else. You are not expected to become a legal expert — but staying organized and responsive matters. Slow response to attorney requests is one of the most common reasons lead plaintiff designations fall apart.
If you are not interested in being the lead plaintiff, you may still qualify for an existing case as a passive class member. Check no-proof settlements to see if you can claim money without any documentation at all.
Frequently Asked Questions
How many people do you need to start a class action lawsuit?
There is no exact minimum, but courts generally require at least 40 potential class members before finding the numerosity requirement satisfied. Cases with hundreds or thousands of members are far easier to certify. The key is that the group must be large enough that joining every person individually would be impractical.
Can one person start a class action by themselves?
Yes — one person can be the named plaintiff and file the class action complaint. However, the lawsuit must allege that there are many others in the same position. You do not need every class member to sign on before filing; the court identifies and notifies class members after certification.
Do you get paid more as the lead plaintiff than other class members?
Yes, typically. Courts can award the lead plaintiff an incentive payment — also called a service award — on top of their share of the class recovery. These payments typically range from $1,000 to $25,000 depending on the time the lead plaintiff invested. Courts scrutinize large incentive awards and sometimes reduce them.
What happens if the class action loses?
If the case loses at trial, class members generally receive nothing and the class action cannot be refiled on the same claim. However, most class actions settle before trial, so a full loss at trial is uncommon. The lead plaintiff owes no money to the attorneys because the case is handled on contingency.
Can you opt out of a class action you did not start?
Yes. Under Rule 23(b)(3) — the most common type for consumer cases — class members have the right to opt out during the notice period. Opting out lets you pursue your own individual lawsuit instead of sharing in the class settlement. You must submit a written opt-out request by the court's deadline or you are bound by the outcome.
What types of cases are best suited for class actions?
Consumer fraud, data breaches, false advertising, defective products, wage theft, ERISA violations, and securities fraud are the most common class action categories. Cases where the defendant's conduct was uniform across all victims — a single policy, a single product defect, or a single data breach — are the best candidates because commonality is easy to establish.
Can a class action be filed in state court instead of federal court?
Yes. Many class actions are filed in state court, particularly employment and consumer protection cases. The Class Action Fairness Act of 2005 (CAFA) allows defendants to remove large class actions to federal court when the total damages exceed $5 million and parties are from different states. Your attorney will choose the venue that gives the class the best chance of certification.
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