Why this is mistaken
Begin with buyer substitution and entry, not a brand boundary. One seller in a supported market still faces demand, cost, capacity, regulation, buyer-power, resale, innovation, and entry constraints.
Then separate economic structure from law. A legal conclusion requires the jurisdiction's current rule, a defined market or other permitted framework, power, conduct, effects, defenses, procedure, and evidence. Historical cases provide context, not automatic current outcomes.
Where to watch
When this mistake may appear
- One seller supplies a named brand or legal product category.
- A dominant firm changes price or terms.
Check your work
Your work may contain this mistake if:
- Defines the relevant market as everything one company sells.
- Says a monopolist can choose any price without losing demand.
- Equates monopoly status with an antitrust violation without conduct or current law.