The Clayton Antitrust Act is a 1914 federal law that targets specific business practices likely to reduce competition or push toward monopoly, including price discrimination, anticompetitive mergers, tying arrangements, and shared directors between competing companies. It also lets private businesses and individuals sue violators in federal court for three times their actual losses. Enforcement is split between the Federal Trade Commission and the Department of Justice’s Antitrust Division, with the specific prohibitions codified across sections of Title 15 of the U.S. Code.
Price Discrimination
Under 15 U.S.C. § 13, later strengthened by the Robinson-Patman Act, a seller cannot charge different buyers different prices for goods of the same grade and quality when the price gap could substantially weaken competition or tend to create a monopoly in any line of commerce.1Office of the Law Revision Counsel. 15 USC 13 – Discrimination in Price, Services, or Facilities The provision reaches physical goods sold within the United States. Pure service contracts sit outside it.
Two defenses matter most. A seller can justify different prices by showing the difference reflects genuine variation in the cost of manufacturing, shipping, or selling the product, so a buyer 500 miles away can be charged more than one 50 miles away without violating the law. A seller can also drop its price to a specific customer in good faith to match a competitor’s lower offer.1Office of the Law Revision Counsel. 15 USC 13 – Discrimination in Price, Services, or Facilities Rebates, promotional allowances, or advertising credits handed to favored buyers while their competitors get nothing are treated as price discrimination unless the benefits are made available to all competing buyers on proportionally equal terms.
Tying Arrangements and Exclusive Dealing
Section 3 of the Act, 15 U.S.C. § 14, prohibits two connected practices. Tying is conditioning the sale of one product on the buyer also taking a second, different product. Exclusive dealing is requiring the buyer to stop purchasing from the seller’s competitors as a condition of the deal. Both are illegal when they may substantially lessen competition or tend to create a monopoly.2Office of the Law Revision Counsel. 15 USC 14 – Sale, Etc., on Agreement Not to Use Goods of Competitor
Bundling and long-term supply arrangements are not automatically unlawful. Courts look at whether the seller has enough market power in the tying product to coerce buyers into the second product, and whether a meaningful share of commerce in that second product is affected. In one Supreme Court case, a hospital with a 30 percent market share was found to lack sufficient power for a tying claim to succeed. Small players rarely face liability under this section; dominant firms that force customers into package deals often do.
Mergers and Acquisitions
Section 7, 15 U.S.C. § 18, bars any corporation from acquiring the stock or assets of another when the effect may substantially lessen competition or tend to create a monopoly anywhere in the country.3Office of the Law Revision Counsel. 15 USC 18 – Acquisition of Stock, Assets, Etc. It reaches horizontal deals between direct competitors and vertical deals between a company and its suppliers or distributors. Regulators do not have to wait until a monopoly forms. If they can show a transaction would likely raise prices, cut consumer choice, or make coordination among remaining firms easier, the deal can be blocked.
Merging companies sometimes raise a “failing firm” defense, arguing the target would exit the market anyway. It is a hard defense to win. The acquirer must show that the target cannot meet its financial obligations in the near future, cannot reorganize through bankruptcy, and has made genuine but unsuccessful efforts to find a less anticompetitive buyer.4U.S. Department of Justice. Failing Firm Defense – Contribution by the United States The full burden of proof sits on the defendant.
Premerger Notification Under Hart-Scott-Rodino
The Hart-Scott-Rodino Antitrust Improvements Act of 1976, at 15 U.S.C. § 18a, layered a mandatory notification process on top of Section 7. Before closing a deal that clears certain dollar thresholds, both the acquiring and target companies file a notification with the FTC and the DOJ Antitrust Division and then wait before completing the transaction.5Office of the Law Revision Counsel. 15 USC 18a – Premerger Notification and Waiting Period
The standard waiting period is 30 days from receipt of completed filings. Cash tender offers get a shorter 15-day window. The agencies can end the wait early when they see no concern, or extend it by issuing a “second request” for more information, which resets the clock for another 30 days.5Office of the Law Revision Counsel. 15 USC 18a – Premerger Notification and Waiting Period
Thresholds adjust yearly with gross national product. Effective February 17, 2026, the key numbers are:
- A filing is required when the acquiring company would hold more than $133.9 million in the target’s voting securities or assets.
- For transactions between $133.9 million and $535.5 million, a size-of-person test applies: one party must have at least $26.8 million in total assets or annual net sales and the other at least $267.8 million.
- Transactions above $535.5 million require a filing regardless of the parties’ sizes.
Filing fees in 2026 run from $35,000 for smaller reportable deals up to $2,460,000 for transactions of $5.869 billion or more, with tiers in between.6Federal Trade Commission. New HSR Thresholds and Filing Fees for 2026 Closing a reportable deal without filing exposes the parties to civil penalties for each day of noncompliance.
Interlocking Directorates
Section 8, 15 U.S.C. § 19, prohibits the same person from serving as a director or officer of two competing corporations at the same time. The concern is straightforward: shared leadership between rivals invites coordination on price or market allocation. The bar applies when both corporations are engaged in commerce and compete in a way that any agreement between them to eliminate that competition would violate antitrust law.7Office of the Law Revision Counsel. 15 USC 19 – Interlocking Directorates and Officers
The restriction only reaches corporations above a size threshold that the FTC updates each year. For 2026, the threshold under Section 8(a)(1) is $48,948,000 in combined capital, surplus, and undivided profits. Even above that threshold, a de minimis exception permits an interlock when the competitive overlap is small: for 2026 the Section 8(a)(2)(A) figure is $4,894,800 in competitive sales.8Federal Trade Commission. Revised Jurisdictional Thresholds for Section 8 of the Clayton Act Two large companies whose product lines barely touch can share a board member without running into Section 8.
Labor and Agricultural Carve-Outs
The Act states plainly that human labor is not a commodity or article of commerce. Under 15 U.S.C. § 17, labor unions, agricultural cooperatives, and horticultural organizations carrying out their legitimate purposes are exempt from antitrust liability.9Office of the Law Revision Counsel. 15 USC 17 – Antitrust Laws Not Applicable to Labor Organizations Collective bargaining over wages and cooperative marketing by farmers are not treated as illegal conspiracies in restraint of trade.
The exemption is not unlimited. It covers organizations operating for mutual benefit, without capital stock, and without a profit motive. A union that goes beyond legitimate collective bargaining, or an agricultural group operating as a for-profit venture, can lose the shield and face the same antitrust scrutiny as any other business.
Who Enforces the Act
The FTC and the DOJ Antitrust Division share enforcement responsibility.10Federal Trade Commission. The Antitrust Laws The FTC brings administrative proceedings; the DOJ files civil suits in federal court. The agencies coordinate to avoid duplication, with the FTC typically handling reviews in healthcare, retail, and technology and the DOJ taking banking, telecommunications, and airlines.
Private Lawsuits and Treble Damages
One of the Act’s defining features is its private right of action. Under 15 U.S.C. § 15, any person or business injured by an antitrust violation can sue in federal court and recover three times the actual damages, plus reasonable attorney’s fees and litigation costs.11Office of the Law Revision Counsel. 15 USC 15 – Suits by Persons Injured A company with $2 million in provable losses from a price-fixing scheme could recover $6 million and its legal fees. Trebling is what makes private antitrust suits financially viable for plaintiffs and painful enough for defendants to work as a deterrent.
Standing has one major federal limit. In Illinois Brick Co. v. Illinois, the Supreme Court held that only direct purchasers can sue for treble damages under the Clayton Act.12Justia. Illinois Brick Co. v. Illinois, 431 US 720 (1977) When a manufacturer fixes prices and sells to a distributor, who sells to a retailer, who sells to a consumer, only the distributor has federal standing. Many states have passed their own laws opening the door to indirect-purchaser claims.
Injunctions
Money damages are not the only remedy. Under 15 U.S.C. § 26, a private party facing imminent loss from an antitrust violation, including the Clayton Act’s specific bans on price discrimination, tying, harmful mergers, and interlocking directorates, can ask a federal court to stop the conduct.13Office of the Law Revision Counsel. 15 USC 26 – Injunctive Relief for Private Parties A plaintiff who substantially prevails on an injunction claim also recovers attorney’s fees and costs.
Four-Year Deadline
Private plaintiffs have four years from the date a Clayton Act cause of action accrues to sue. Miss that window and the claim is permanently barred under 15 U.S.C. § 15b.14Office of the Law Revision Counsel. 15 USC 15b – Limitation of Actions Figuring out when the clock started can be difficult. Courts have sometimes found that in ongoing conspiracies or concealed conduct, the period restarts with each new overt act, or only begins when the plaintiff discovered, or reasonably should have discovered, the violation. Four years sounds generous, but antitrust injuries often take time to detect, and that is where most private claims stumble.