At issue are the following provisions in 29 USC 1003(b)(2):
(33)(A) The term “church plan” means a plan established and maintained . . . by a church or by a convention or association of churches....
(C) For purposes of this paragraph— (i) A plan established and maintained for its employees (or their beneficiaries) by a church or by a convention or association of churches includes a plan maintained by an organization ... [which] is controlled by or associated with a church or a convention or association of churches.The religiously affiliated health care systems in these cases, rather than the churches they are affiliated with, created the retirement plans for their employees. In 1983 in a General Counsel Memorandum, the Internal Revenue Service took the position that it is sufficient if the retirement plan was is maintained by a religiously affiliated organization, even if it was initially created by that organization and not the "church" it was affiliated with. In a series of cases filed around the country, plan beneficiaries have attacked that conclusion and in the cases in which the Court today granted certiorari the plan beneficiaries prevailed. If the Supreme Court affirms these Circuit Court decisions, retirement plans of various religiously-affiliated organizations will be undefunded in total by billions of dollars.
SCOTUSblog has case pages for each of the cases (case page for Advocate Health Care case with links to case pages for other two cases).