Antitrust laws are the federal statutes that protect competition by prohibiting businesses from fixing prices, dividing markets, monopolizing industries, or merging in ways that eliminate meaningful rivalry. Three statutes carry most of the load: the Sherman Act, the Clayton Act, and the Federal Trade Commission Act. Criminal violations of the Sherman Act can bring fines of up to $100 million for a corporation and up to 10 years in prison for an individual, and anyone injured by an antitrust violation can sue for three times their actual losses plus attorney’s fees.
The Three Core Federal Statutes
The Sherman Act, enacted in 1890, is the foundation. Section 1 makes it a felony to enter any contract or conspiracy that restrains trade among the states or with foreign nations, punishable by fines of up to $100 million for a corporation, or up to $1 million and 10 years in prison for an individual.1Office of the Law Revision Counsel. 15 USC 1 – Trusts, Etc., in Restraint of Trade Illegal; Penalty Section 2 targets monopolization on the single-firm level, making it a felony to monopolize, attempt to monopolize, or conspire to monopolize any part of trade or commerce, with the same penalty structure.2Office of the Law Revision Counsel. 15 USC 2 – Monopolizing Trade a Felony; Penalty
Congress passed the Clayton Act in 1914 to fill gaps the Sherman Act’s broad language didn’t clearly reach. Section 7 prohibits any merger or acquisition where the effect may be to substantially lessen competition or tend to create a monopoly.3Office of the Law Revision Counsel. 15 USC 18 – Acquisition by One Corporation of Stock of Another Section 8 bars the same person from serving as a director or officer of two competing corporations above a size threshold the FTC adjusts annually for inflation.4Office of the Law Revision Counsel. 15 USC 19 – Interlocking Directorates and Officers The Clayton Act also created the private treble-damages remedy that lets injured parties sue on their own.
The Federal Trade Commission Act established the FTC and gave it authority to police both unfair methods of competition and deceptive business practices. Section 5 declares those acts unlawful in commerce.5Office of the Law Revision Counsel. 15 USC 45 – Unfair Methods of Competition Unlawful The language is deliberately wider than the Sherman and Clayton Acts, allowing the FTC to reach conduct that damages competition even when it technically falls outside those older statutes.6Federal Trade Commission. Federal Trade Commission Act
A fourth statute, the Robinson-Patman Act, addresses price discrimination. It makes it unlawful for a seller to charge different prices to competing buyers of commodities of the same grade and quality when the price difference is likely to substantially lessen competition.7Office of the Law Revision Counsel. 15 USC 13 – Discrimination in Price, Services, or Facilities It covers only physical goods sold in interstate commerce, not services or intangibles, and a seller has a defense if the price difference reflects real cost differences or was offered in good faith to meet a competitor’s price.
What Antitrust Laws Prohibit
Agreements Among Competitors
The most frequently prosecuted violations involve rival businesses secretly agreeing to rig the market instead of competing in it. Price-fixing is an agreement among competitors to set, raise, or stabilize prices. Bid-rigging is coordination among companies that are supposed to compete for a contract to decide who wins. Market allocation is rivals carving up territories or customer groups so they don’t have to compete head-to-head. Group boycotts, in which two or more firms refuse to deal with a supplier, customer, or competitor to punish or exclude them, round out the category. Under federal enforcement policy, these schemes are treated as automatically illegal once the agreement is proven, no matter how reasonable the resulting prices might look.8U.S. Department of Justice. Price Fixing, Bid Rigging, and Market Allocation Schemes
No-Poach and Wage-Fixing
Employer agreements not to recruit or hire each other’s workers, or to fix wages at a set level, are a more recent enforcement frontier. The DOJ announced in 2016 that it would treat these labor-market agreements as criminal Sherman Act violations when they are stand-alone deals between competing employers rather than part of a legitimate joint venture. An employee who suspects their employer agreed with a competitor not to compete for their labor may have grounds for a private claim.
Vertical Restraints and Tying
Not every anticompetitive agreement is between direct rivals. Vertical restraints involve companies at different levels of the supply chain, such as a manufacturer and a retailer. A common example is a tying arrangement, where a seller conditions the sale of one product on the buyer also purchasing a second, separate product. Tying raises antitrust concerns when the seller has enough market power in the first product to coerce the purchase of the second. Courts now analyze most tying claims under a flexible reasonableness standard rather than treating them as automatically illegal.9Federal Trade Commission. Tying the Sale of Two Products
Monopolization
Holding a monopoly is not itself illegal. A company that dominates its market because it built a better product or out-executed everyone else hasn’t broken the law. The violation under Section 2 of the Sherman Act is using exclusionary tactics to gain or maintain monopoly power, meaning winning by blocking rivals rather than on the merits.2Office of the Law Revision Counsel. 15 USC 2 – Monopolizing Trade a Felony; Penalty
Predatory pricing is one classic example: a dominant firm sets prices below its own costs to drive smaller rivals out, planning to raise prices later once they’re gone. The FTC notes this strategy is actually rare because it requires the predator to absorb significant short-term losses with no guarantee of recouping them. Aggressive price cutting is not illegal unless it’s part of a deliberate strategy to eliminate competitors and there’s a realistic probability the firm will achieve monopoly power as a result.10Federal Trade Commission. Predatory or Below-Cost Pricing Refusal to deal is another tricky area. Businesses generally have the right to choose their trading partners, but when a monopolist controls access to a critical input and cuts off rivals specifically to prevent them from competing, courts can treat that refusal as an antitrust violation. These claims are difficult to win in practice.
Per Se Violations Versus the Rule of Reason
Courts use two different frameworks to decide whether a business practice violates antitrust law, and the choice essentially determines how hard the case is to prove.
Some conduct is so plainly harmful to competition that courts declare it illegal on its face, with no need to study its actual market effects. Price-fixing, bid-rigging, and market allocation among competitors all fall into this per se category.8U.S. Department of Justice. Price Fixing, Bid Rigging, and Market Allocation Schemes Once the government proves the agreement existed, it doesn’t matter that the agreed prices seem reasonable or that the companies were trying to avoid destructive competition. The agreement itself is the crime.
Everything else is evaluated under the rule of reason, a balancing test that weighs the competitive benefits of a practice against its harms. Courts examine the defendant’s market share, the purpose of the restraint, and whether consumers are better or worse off. Most antitrust cases end up here, and the analysis is far more fact-intensive and expensive to litigate. Even a practice that looks unfair can be hard to prove illegal without substantial expert economic testimony showing harm across a relevant market.
Merger Review Under the HSR Act
The Clayton Act’s ban on anticompetitive mergers is enforced largely through a pre-closing review process created by the Hart-Scott-Rodino Antitrust Improvements Act. Before completing certain large acquisitions, the parties must file a notification with both the FTC and the DOJ Antitrust Division and then wait for the agencies to assess the deal.11Federal Trade Commission. Hart-Scott-Rodino Antitrust Improvements Act of 1976
For 2026, the minimum size-of-transaction threshold that triggers a mandatory HSR filing is $133.9 million, effective February 17, 2026.12Federal Trade Commission. New HSR Thresholds and Filing Fees for 2026 The standard initial waiting period runs 30 days from the filing date, or 15 days for cash tender offers and certain bankruptcy sales. If either agency wants to investigate further, it can issue a Second Request for additional documents and data, which extends the waiting period for another 30 days after the parties substantially comply.13Federal Register. Premerger Notification; Reporting and Waiting Period Requirements Producing what a Second Request demands can take months and cost millions in legal fees, which is why it is one of the agencies’ most powerful tools.
Who Enforces Antitrust Laws
Two federal agencies share responsibility, and their jurisdictions overlap. Before opening an investigation, the FTC and DOJ consult with each other to avoid duplication, and each has developed expertise in particular industries over the decades.14Federal Trade Commission. The Enforcers
The DOJ Antitrust Division is the only agency that can bring criminal antitrust charges. It prosecutes cartels, price-fixing rings, and other hard-core conspiracies, and it also files civil cases to block mergers or stop anticompetitive conduct.15U.S. Department of Justice. Criminal Enforcement The DOJ has sole antitrust jurisdiction in certain regulated industries, including telecommunications, banking, railroads, and airlines.14Federal Trade Commission. The Enforcers
The FTC enforces antitrust law through civil proceedings. It reviews merger filings, investigates unfair competitive practices, and can bring cases either in federal court or before its own administrative law judges.16Federal Trade Commission. Adjudicative Proceedings
State attorneys general add another layer. Under 15 U.S.C. ยง 15c, any state AG can bring a federal antitrust lawsuit on behalf of state residents to recover damages for Sherman Act violations.17Office of the Law Revision Counsel. 15 USC 15c – Actions by State Attorneys General State AGs frequently work with federal authorities during merger investigations and sometimes file their own challenges when they believe a deal will harm local consumers.
Private Lawsuits and Treble Damages
Federal antitrust law doesn’t rely on government enforcers alone. Section 4 of the Clayton Act gives any person injured in their business or property by an antitrust violation the right to sue in federal court and recover three times their actual damages, plus attorney’s fees and the cost of the suit.18Office of the Law Revision Counsel. 15 USC 15 – Suits by Persons Injured The first third of a treble-damages award compensates real economic harm; the other two-thirds serve as a penalty designed to deter future violations and reward private enforcement.
There are limits on who can sue. Under a longstanding Supreme Court doctrine, only direct purchasers, meaning the parties who bought directly from the violator, can bring federal treble-damages claims. Indirect purchasers further down the supply chain are generally barred from suing under federal law, though many states have passed their own statutes allowing indirect-purchaser claims in state court.
The clock runs fast. A private antitrust action must be filed within four years after the claim accrues, or it is permanently barred.19Office of the Law Revision Counsel. 15 USC 15b – Limitation of Actions Because these cases are expensive and evidence-heavy, most private suits involve either large businesses or well-funded class actions.
Leniency for Companies That Come Forward
The DOJ Antitrust Division operates a leniency program that grants complete immunity from criminal prosecution to the first corporation to report its participation in an antitrust conspiracy. The program has been one of the most effective cartel-detection tools available, because it creates a strong incentive for conspirators to race to the government before their partners do.20U.S. Department of Justice. Antitrust Division Leniency Program To qualify, the company generally must be the first through the door before the Division has information about the conspiracy from another source, must promptly stop its participation, must cooperate fully, must not have been the ringleader, and must make restitution where possible. Leniency covers criminal penalties only. A company that receives it can still face private treble-damages lawsuits from injured parties.
Where Antitrust Laws Don’t Fully Apply
Not every industry or activity is subject to the full force of antitrust enforcement. Labor unions are largely exempt when engaging in collective bargaining, a carve-out dating back to the Clayton Act’s recognition that labor is not a commodity. The insurance industry historically operated under the McCarran-Ferguson Act, which deferred antitrust regulation to the states for the “business of insurance,” though federal enforcement still reaches boycotts, coercion, and intimidation. Professional baseball holds a judicial exemption rooted in a 1922 Supreme Court decision that treated it as outside interstate commerce; Congress narrowed the exemption for major-league player employment through the Curt Flood Act of 1998 but left much of the sport’s business structure covered. Agricultural cooperatives and certain joint export activities have their own narrower statutory exemptions. These carve-outs are the exception, not the rule, and none of them protect naked price-fixing that would violate the Sherman Act in any context.