Editing Sherman Antitrust Act (section)

===Modern trends===
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{{original research section|date=July 2022}}
====Inference of conspiracy====
A modern trend has increased difficulty for antitrust plaintiffs as courts have come to hold plaintiffs to increasing burdens of pleading. Under older Section 1 precedent, it was not settled how much evidence was required to show a conspiracy. For example, a conspiracy could be inferred based on parallel conduct, etc. That is, plaintiffs were only required to show that a conspiracy was conceivable. Since the 1970s, however, courts have held plaintiffs to higher standards, giving antitrust defendants an opportunity to resolve cases in their favor before significant discovery under [[Federal Rules of Civil Procedure|FRCP]] 12(b)(6). That is, to overcome a [[Motion in United States law|motion to dismiss]], plaintiffs, under ''[[Bell Atlantic Corp. v. Twombly]]'', must plead facts consistent with [[Federal Rules of Civil Procedure|FRCP]] 8(a) sufficient to show that a conspiracy is plausible (and not merely conceivable or possible). This protects defendants from bearing the costs of antitrust "fishing expeditions"; however it deprives plaintiffs of perhaps their only tool to acquire evidence (discovery).

=====Manipulation of market=====
Second, courts have employed more sophisticated and principled definitions of markets. Market definition is necessary, in rule of reason cases, for the plaintiff to prove a conspiracy is harmful. It is also necessary for the plaintiff to establish the market relationship between conspirators to prove their conduct is within the per se rule.

In early cases, it was easier for plaintiffs to show market relationship, or dominance, by tailoring market definition, even if it ignored fundamental principles of economics. In ''[[U.S. v. Grinnell]]'', 384 U.S. 563 (1966), the trial judge, [[Charles Wyzanski]], composed the market only of alarm companies with services in every state, tailoring out any local competitors; the defendant stood alone in this market, but had the court added up the entire national market, it would have had a much smaller share of the national market for alarm services that the court purportedly used. The appellate courts affirmed this finding; however, today, an appellate court would likely find this definition to be flawed. Modern courts use a more sophisticated market definition that does not permit as manipulative a definition.{{Citation needed|date=April 2009}}