In the case of CIC Services, LLC v. Internal Revenue Service (2020), CIC Services, a company that advises taxpayers on captive insurance companies, challenged an IRS notice requiring certain transactions to be reported as potentially abusive tax shelters. The Anti-Injunction Act generally prohibits lawsuits seeking to restrain the assessment or collection of taxes before they are assessed. However, CIC argued that this rule should not apply because it was challenging a regulatory mandate separate from any tax liability. The district court and Sixth Circuit Court dismissed their suit based on the Anti-Injunction Act's bar against pre-enforcement challenges to tax regulations. However, in May 2021, the Supreme Court ruled in favor of CIC Services by a vote of 9-0 stating that although violations could result in penalties which were treated as taxes under law; these penalties were not necessarily 'taxes' for purposes of the Anti-Injunction Act. This ruling allowed CIC’s lawsuit against IRS reporting requirements to proceed without waiting for enforcement action by arguing its challenge targeted rules governing conduct outside taxation itself.

In the dissenting opinion for CIC Services, LLC v. Internal Revenue Service, Justice Sotomayor argued that the majority's decision to allow pre-enforcement judicial review of IRS reporting requirements undermines Congress' intent in drafting the Anti-Injunction Act (AIA). She contended that this ruling could open floodgates to lawsuits challenging tax regulatory actions before they are enforced, thereby disrupting tax administration and revenue collection. The justice also expressed concern about potential abuse by taxpayers who might use litigation as a tactic to delay or evade their obligations. Furthermore, she disagreed with the majority's interpretation of "taxes" under AIA and its distinction between penalties imposed for violating tax regulations versus those associated directly with non-payment of taxes. In her view, both types should be treated equally under AIA because they serve similar purposes in promoting compliance with tax laws.