Opinion of the Court
tional Part A coverage. Allina Health Services v. Price, 863 F. 3d 937, 939 (CADC 2017). So counting them makes the fraction smaller and reduces hospitals’ payments considerably—by between $3 and $4 billion over a 9-year period, according to the government. Pet. for Cert. 23.
The agency overseeing Medicare has gone back and forth on whether to count Part C participants in the Medicare fraction. At first, it did not include them. See Northeast Hospital Corp. v. Sebelius, 657 F. 3d 1, 15–16 (CADC 2011). In 2003, the agency even proposed codifying that practice in a formal rule. 68 Fed. Reg. 27208. But after the public comment period, the agency reversed field and issued a final rule in 2004 declaring that it would begin counting Part C patients. 69 Fed. Reg. 49099. This abrupt change prompted various legal challenges from hospitals. In one case, a court held that the agency couldn’t apply the 2004 rule retroactively. Northeast Hospital, 657 F. 3d, at 14. In another case, a court vacated the 2004 rule because the agency had “ ‘pull[ed] a surprise switcheroo’ ” by doing the opposite of what it had proposed. Allina Health Services v. Sebelius, 746 F. 3d 1102, 1108 (CADC 2014). Eventually, and in response to these developments, the agency in 2013 issued a new rule that prospectively “readopt[ed] the policy” of counting Part C patients. 78 Fed. Reg. 50620. Challenges to the 2013 rule are pending.
The case before us arose in 2014. That’s when the agency got around to calculating hospitals’ Medicare fractions for fiscal year 2012. When it did so, the agency still wanted to count Part C patients. But it couldn’t rely on the 2004 rule, which had been vacated. And it couldn’t rely on the 2013 rule, which bore only prospective effect. The agency’s solution? It posted on a website a spreadsheet announcing the 2012 Medicare fractions for 3,500 hospitals nationwide and noting that the fractions included Part C patients.
