15 U.S.C. § 1 · A outline

Encompasses two distinct sub-inquiries: (1) capacity/plurality of actors (Copperweld Corp. v. Independence Tube Corp., 467 U.S. 752 (1984); American Needle), and (2) existence/proof of an actual agreement rather than unilateral conduct (United States v. Colgate & Co., 250 U.S. 300 (1919)) or mere conscious parallelism (Twombly; Matsushita).

17 merits instance blocks; 9 distinct cases

• OR Conditional Monsanto / Matsushita inference: evidence tending to exclude the possibility of independent action when circumstantial proof is used

  This is a conditional evidentiary inference used when the alleged agreement is proved circumstantially; it is not a universal additional element where direct agreement evidence is offered. Under Monsanto (465 U.S. at 764) and Matsushita (475 U.S. at 588), circumstantial evidence must tend to exclude independent action.

  0 merits instance blocks; 0 distinct cases

  Recorded DB variant labels, including zero-count variants

  Variant	Description	Merits instance blocks	Distinct cases	Example cases (up to 3 per group)
  express-tie/buyer-acquiescence-excludes-independent-action		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /f3d/117/1137-01 — United States Court of Appeals for the Tenth Circuit · 1997 — rule-announced/merits

Under Summit Health, Ltd. v. Pinhas (500 U.S. 322 (1991)) and McLain v. Real Estate Board of New Orleans (444 U.S. 232 (1980)), satisfied if the restraint is either "in" interstate commerce or concerns general business activities that have a "not insubstantial effect" on interstate commerce (and for foreign commerce, subject to the Foreign Trade Antitrust Improvements Act, 15 U.S.C. § 6a).

0 merits instance blocks; 0 distinct cases

Under Brunswick Corp. v. Pueblo Bowl-O-Mat, Inc. (429 U.S. 477, 489 (1977)), plaintiff must prove "antitrust injury, which is to say injury of the type the antitrust laws were intended to prevent and that flows from that which makes defendants' acts unlawful" — harm to competition, not merely harm to an individual competitor.

3 merits instance blocks; 2 distinct cases

• AND Quantum / reasonable estimate of antitrust damages once fact of damage is established

  Courts distinguish between the strict burden of proving the *fact* of antitrust injury/damage and the more relaxed standard for estimating the *amount* of damages (Story Parchment Co. v. Paterson Parchment Paper Co., 282 U.S. 555 (1931); Bigelow v. RKO Radio Pictures, 327 U.S. 251 (1946)).

  1 merits instance blocks; 1 distinct cases

  Recorded DB variant labels, including zero-count variants

  Variant	Description	Merits instance blocks	Distinct cases	Example cases (up to 3 per group)
  amount-of-damages/lost-profits-estimated-from-past-earnings		1 Satisfied 1; not satisfied 0; excluded context 0	1	/f2d/361/0874-01 — United States Court of Appeals for the First Circuit · 1966 — satisfied

In civil cases, unlawful intent or anticompetitive effect suffices (United States v. U.S. Gypsum Co., 438 U.S. 422, 436 n.13 (1978)). In non-per-se criminal prosecutions (Gypsum), the government must prove either knowledge that the conduct would produce anticompetitive effects or purpose to produce them; in per se criminal prosecutions, knowing joinder in the price-fixing/allocation agreement suffices.

0 merits instance blocks; 0 distinct cases

Because every commercial contract restrains trade in some literal sense, § 1 outlaws only *unreasonable* restraints of trade (Standard Oil Co. v. United States, 221 U.S. 1 (1911); State Oil Co. v. Khan, 522 U.S. 3, 10 (1997)), evaluated via one of three analytical modes (`restraint.per-se`, `restraint.quick-look`, or `restraint.rule-of-reason`).

0 merits instance blocks; 0 distinct cases

• AND Relevant product/geographic market definition and market power under the Rule of Reason

  Under the Rule of Reason (absent direct proof of actual detrimental effects on price or output under FTC v. Indiana Federation of Dentists, 476 U.S. 447 (1986)), plaintiff must define a relevant product and geographic market and prove defendants possess market power within it.

  0 merits instance blocks; 0 distinct cases

  Recorded DB variant labels, including zero-count variants

  Variant	Description	Merits instance blocks	Distinct cases	Example cases (up to 3 per group)
  rule-of-reason-factor/market-power-of-manufacturer-or-retailer		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /us/551/0877-01 — Supreme Court of the United States · 2007 — rule-announced/merits
  Unspecified variant	No variant assigned in the database.	0 Satisfied 0; not satisfied 0; excluded context 4	0	No counted merits examples Excluded context examples: /f-supp-2d/385/0740-01 — United States District Court for the Northern District of Illinois · 2005 — rule-announced/merits; /f-supp/864/1175-01 — United States District Court for the Middle District of Florida · 1994 — applied/alternative; /f3d/117/1137-01 — United States Court of Appeals for the Tenth Circuit · 1997 — rule-announced/merits

• OR Per se illegality for naked restraints manifestly anticompetitive and lacking redeeming virtue

  Reserved for horizontal price fixing (Socony-Vacuum), bid rigging, horizontal market/customer allocation (Palmer v. BRG; Cooperative Theatres), certain horizontal group boycotts denying access to an essential facility/market (Northwest Wholesale Stationers; Tunica Web), and tying where the seller has appreciable economic power in the tying product market (Jefferson Parish). Vertical minimum and maximum resale price maintenance are no longer per se unlawful (Leegin, 551 U.S. 877 (2007); State Oil v. Khan, 522 U.S. 3 (1997)).

  4 merits instance blocks; 3 distinct cases

  Recorded DB variant labels, including zero-count variants

  Variant	Description	Merits instance blocks	Distinct cases	Example cases (up to 3 per group)
  ancillary-restraint/cooperative-buying-through-common-agent		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /f-supp-2d/385/0740-01 — United States District Court for the Northern District of Illinois · 2005 — rule-announced/merits
  group-boycott/horizontal-buyers-boycotting-non-competitor-supplier		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /f3d/496/0403-01 — United States Court of Appeals for the Fifth Circuit · 2007 — rule-announced/merits
  horizontal-customer-allocation/no-solicitation-of-existing-accounts	Naked horizontal agreement between competitors not to solicit each other's existing customers (Cooperative Theatres)	1 Satisfied 1; not satisfied 0; excluded context 0	1	/f2d/845/1367-01 — United States Court of Appeals for the Sixth Circuit · 1988 — satisfied
  horizontal-price-fixing/competing-intermediaries-fixing-reimbursement-rates		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /f-supp-2d/385/0740-01 — United States District Court for the Northern District of Illinois · 2005 — rule-announced/merits
  no-per-se/single-price-set-by-lawful-integrated-joint-venture	Unified pricing by an economically integrated joint venture is not per se unlawful (Texaco v. Dagher)	0 Satisfied 0; not satisfied 0; excluded context 0	0	No annotation uses in this snapshot
  per-se-rejected/closed-panel-ppo-effect-not-obvious		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /f-supp/864/1175-01 — United States District Court for the Middle District of Florida · 1994 — rule-announced/alternative
  per-se-rejected/cooperation-essential-to-product		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /us/560/0183-01 — Supreme Court of the United States · 2010 — rule-announced/merits
  per-se-rejected/single-price-set-by-lawful-integrated-joint-venture		1 Satisfied 0; not satisfied 1; excluded context 0	1	/us/547/0001-01 — Supreme Court of the United States · 2006 — not
  per-se-rejected/vertical-minimum-resale-price-maintenance		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /us/551/0877-01 — Supreme Court of the United States · 2007 — rule-announced/merits
  per-se/vertical-agreements-to-exclude-class-of-resellers		1 Satisfied 1; not satisfied 0; excluded context 0	1	/f2d/361/0874-01 — United States Court of Appeals for the First Circuit · 1966 — satisfied
  quick-look-rejected/single-price-set-by-lawful-integrated-joint-venture		1 Satisfied 0; not satisfied 1; excluded context 0	1	/us/547/0001-01 — Supreme Court of the United States · 2006 — not

• OR Quick-look / truncated Rule of Reason analysis for restraints with obvious anticompetitive effects

  Applied when "an observer with even a rudimentary understanding of economics could conclude that the arrangements in question would have an anticompetitive effect on customers and markets" (California Dental Ass'n v. FTC, 526 U.S. 756, 770 (1999); NCAA v. Board of Regents, 468 U.S. 85 (1984)).

  0 merits instance blocks; 0 distinct cases

  No variants recorded in this snapshot.

• OR Presumptive Rule of Reason burden-shifting analysis (antitrust market + anticompetitive effect vs procompetitive justification)

  Default standard under § 1 (Ohio v. American Express Co., 585 U.S. 529 (2018); Leegin): three-step burden-shifting framework: (1) plaintiff proves substantial anticompetitive effect in a defined relevant product and geographic market (directly via reduced output/supercompetitive prices, or indirectly via market power + anticompetitive structure); (2) defendant proffers nonpretextual procompetitive justifications; (3) plaintiff shows the efficiencies could be reasonably achieved through less anticompetitive means.

  0 merits instance blocks; 0 distinct cases

  Recorded DB variant labels, including zero-count variants

  Variant	Description	Merits instance blocks	Distinct cases	Example cases (up to 3 per group)
  anticompetitive-effect/single-competitor-excluded-no-market-proof		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /f-supp/864/1175-01 — United States District Court for the Middle District of Florida · 1994 — applied/alternative
  rule-of-reason/vertical-minimum-resale-price-maintenance		0 Satisfied 0; not satisfied 0; excluded context 1	0	No counted merits examples Excluded context examples: /us/551/0877-01 — Supreme Court of the United States · 2007 — rule-announced/merits
  Unspecified variant	No variant assigned in the database.	0 Satisfied 0; not satisfied 0; excluded context 5	0	No counted merits examples Excluded context examples: /f-supp-2d/385/0740-01 — United States District Court for the Northern District of Illinois · 2005 — rule-announced/merits; /f2d/361/0874-01 — United States Court of Appeals for the First Circuit · 1966 — applied/merits; /f3d/496/0403-01 — United States Court of Appeals for the Fifth Circuit · 2007 — applied/merits

Under Associated General Contractors of Cal., Inc. v. Carpenters (459 U.S. 519 (1983)), courts balance: (1) causal connection and antitrust injury, (2) directness of the injury (and the Illinois Brick bar on indirect-purchaser damages suits), (3) speculative nature of damages, (4) risk of duplicative recovery or complex apportionment, and (5) existence of more direct victims ("efficient enforcer" factors).

1 merits instance blocks; 1 distinct cases

Under Parker v. Brown (317 U.S. 341 (1943)) and California Retail Liquor Dealers Ass'n v. Midcal Aluminum, Inc. (445 U.S. 97 (1980)), state-action immunity shields non-sovereign/private actors only when (1) the challenged restraint is clearly articulated and affirmatively expressed as state policy, and (2) the policy is actively supervised by the State itself (and hybrid state-mandated pricing rules that compel private per se conduct without active supervision are preempted, 324 Liquor / Schwegmann / Connecticut Fine Wine).

1 merits instance blocks; 1 distinct cases

Accrues when a defendant commits an overt act that injures the plaintiff's business (Zenith Radio Corp. v. Hazeltine Research, Inc., 401 U.S. 321, 338 (1971)), subject to continuing-violation and fraudulent-concealment doctrines; criminal conspiracies run from the last overt act in furtherance of the conspiracy (United States v. Kissel; United States v. Kemp & Assocs.).

0 merits instance blocks; 0 distinct cases

Distinguishes naked restraints (per se) from restraints reasonably ancillary to an efficiency-enhancing integration or cooperative venture (evaluated under the Rule of Reason), though Dagher holds core activity of a lawful integrated joint venture (setting the price of its own product) does not even implicate the ancillary-restraints inquiry.

1 merits instance blocks; 1 distinct cases

Even after Leegin placed vertical resale price maintenance under the Rule of Reason, a horizontal cartel among competing retailers or manufacturers Policed via vertical agreements remains per se unlawful.

0 merits instance blocks; 0 distinct cases

Procedural defense invoked where prior rulings in a multidistrict litigation address overlapping conspiracy allegations.

0 merits instance blocks; 0 distinct cases

Mirror image of `agreement` plurality: a parent corporation and its wholly owned subsidiary (Copperweld, 467 U.S. 752 (1984)), or a corporation and its officers/employees/agents acting on its behalf (Harvey v. Fearless Farris), are a single economic actor incapable of conspiring under § 1; however, legally single joint ventures controlled by separate potential competitors acting on separate economic interests are not immune (American Needle).

1 merits instance blocks; 1 distinct cases