Graphic Argument Explainer: Cyan v. Beaver County Employees Retirement Fund (Supreme Court November 28, 2017)
The retirement fund sued Cyan for misleading in its public offering documents. This case is about whether the plaintiffs' choice to file in state court is valid.
The case involves "forum shopping" - when plaintiffs "shop around" for the court that will best suit their case. Here, the retirement fund chose to file in state court, which has fewer restrictions on their type of claim and makes the case easier for plaintiffs to win.
Cyan is the defendant and (obviously) wants the case to have more restrictions on the plaintiffs. Cyan found a possible interpretation of the law responsible for determining jurisdiction. Cyan argues the law says that certain class actions (those with 50 or more plaintiffs) cannot proceed in federal court.
Some legal interpretation issues (like this one) come from there being one or more edits to a given provision.
In this case, the original law relating to this type of lawsuit, the Securities Act of 1933, was edited a couple of times. Within the edits, class actions (with 50 or more plaintiffs) were given a certain type of restriction, while at the same time the provision on jurisdiction (what cases can go in state versus federal court) changed. Cyan and the retirement fund disagree on how the class action definition got carried over into the jurisdiction provision.
You can read the details of the textual arguments if you want to try to guess who will win, or if you are concerned with the principles of statutory interpretation. Here are the briefs: