On June 21, 2021, the U. S. Supreme Court declined to hear Eric D. Speidell, et al., Petitioners v. United States, which sought to overturn the Tenth Circuit Court of Appeals’ 2020 opinion on Speidell v. United States. In that case, the Tenth Circuit rejected the argument of several Colorado medical marijuana dispensaries that the Internal Revenue Service (IRS) does not have authority to investigate whether a taxpayer is dealing in controlled substances. Because the Supreme Court declined to hear the case, the Tenth Circuit ruling stands, and taxpayers can reasonably expect courts across the country to reach similar results as the Tenth Circuit did. Marijuana-related businesses can expect the IRS to continue aggressively enforcing Section 280E of the Internal Revenue Code.