In the United States v. Penner Installation Corp., 1950, the Supreme Court dealt with a case involving tax evasion. The respondent, Penner Installation Corporation, was accused of evading taxes by overvaluing its inventory and underreporting its income for two years. The corporation argued that it had made an honest mistake in calculating its inventory value due to confusion about accounting methods and should not be penalized for fraud. However, the government contended that this was a deliberate act of tax evasion as there were clear indications of fraudulent intent such as false entries in books and records along with other irregularities. The court ruled against Penner Installation Corporation stating that even if they did make an error due to misunderstanding or ignorance about proper accounting procedures, it does not absolve them from their responsibility to accurately report their income for taxation purposes. Furthermore, evidence presented by the government suggested intentional wrongdoing rather than mere negligence on part of the corporation. This decision underscored corporations' obligation towards accurate financial reporting irrespective of any alleged misunderstandings regarding accounting practices while also emphasizing on severe penalties associated with fraudulent activities aimed at evading taxes.

The dissenting opinion in the United States v. Penner Installation Corp., 1950 case argued that the majority's interpretation of Section 2(a) of the Clayton Act was too broad and could potentially lead to unjust outcomes. The dissenting justices believed that this section should only apply when a price discrimination has been made with an intent to lessen competition or create a monopoly, not simply when it may have such effects. They also disagreed with the majority's view on injury, arguing that actual harm must be shown rather than just potential for harm. Furthermore, they expressed concern over how this ruling might impact small businesses who often rely on discounts from suppliers to compete against larger firms.