Companion cases are cases decided by the Supreme Court on the same day when they involve the same issues or issues that are closely related. Sometimes a single opinion is used to explain two or more companion cases, and sometimes separate opinions are given. Normally the court will select the strongest of a group of companion cases for explanation in a full opinion, leaving the weaker cases to be discussed only briefly by relying on the conclusions in the full opinion.
In order to decide companion cases, the court adopt the method of grant and hold. Court will first brief and argue the lead case followed by holding other similar cases by granting review. Once the lead case is decided, the similar cases are remanded to the lower courts to be resolved according to the lead case’s outcome.