In the United States v. Key, Trustee in Bankruptcy case of 1969, the Supreme Court addressed a dispute over tax refunds owed to a bankrupt corporation. The Internal Revenue Service (IRS) claimed that it had priority over other creditors for these funds due to an earlier assessment of taxes against the company. However, Key argued that under Section 64a(4) of the Bankruptcy Act, he was entitled to distribute these funds among all unsecured creditors equally. The Supreme Court ruled in favor of Key and held that IRS did not have priority claim on tax refunds arising from carryback losses incurred by a bankrupt taxpayer after bankruptcy proceedings began but before adjudication was completed. Instead, such refunds were considered part of the debtor's estate available for distribution among all unsecured creditors according to their respective priorities under federal bankruptcy law.

The dissenting opinion in the case of United States v. Key, Trustee in Bankruptcy, 1969 argued that the majority's decision to allow a trustee in bankruptcy to avoid a federal tax lien on transferred property was inconsistent with previous rulings and misinterpreted relevant statutes. The dissent contended that under Section 67c of the Bankruptcy Act, only liens which are not valid against certain creditors can be avoided by trustees; however, it was clear from precedent and legislative history that federal tax liens were intended to be valid against all creditors regardless of their knowledge or consent. Therefore, allowing avoidance would undermine this intent and disrupt established principles regarding priority among competing claims on an insolvent debtor's estate. Furthermore, they believed there should be no distinction between general unsecured creditors who had received notice about the lien before bankruptcy proceedings began versus those who did not receive such notice until after proceedings started because both groups were equally protected by law.