Sole Shareholder Is Liable for Corporation's Tax Debt: In U.S. v. Lothringer, 2021 PTC 329 (5th Cir. 2021), the Fifth Circuit affirmed a district court and held that the sole owner of a C corporation, which ran a used car lot, was personally liable for his corporation's failure to pay taxes because the corporation was his alter ego. The Fifth Circuit agreed that the district court was correct in applying Texas law and relying on a slew of undisputed facts, including that the taxpayer was the sole shareholder, officer, director, and owner of the C corporation; exercised complete dominion and control over the corporation; failed to observe certain corporate formalities; loaned substantial money to the corporation; and made payments from the corporate bank account to service personal loans.