In the case of Brown v. Helvering, Commissioner of Internal Revenue in 1933, the U.S Supreme Court ruled on a matter concerning income tax deductions. The petitioner, Mr. Brown had claimed an income tax deduction for losses incurred due to loans he made to his corporation which later became worthless when the company went bankrupt. However, this claim was denied by the Commissioner of Internal Revenue and upheld by lower courts who argued that these were not true debts but rather contributions to capital since there was no expectation or intention for repayment at any specific time or under any specific circumstances. The Supreme Court affirmed this decision stating that a genuine debt arises from a debtor-creditor relationship based upon an enforceable obligation to pay a fixed sum of money absolutely and without contingencies. In contrast with equity investments where return is dependent on success or failure of business venture and has no absolute maturity date nor obligation for payment except out of earnings and profits if available after all corporate debts are paid off. Therefore, it concluded that Mr.Brown's advances were more akin to equity investment than loan hence they cannot be considered as bad debts deductible under applicable provisions in revenue acts.

In the dissenting opinion for Brown v. Helvering, Justice Cardozo disagreed with the majority's interpretation of tax law and its application to this case. He argued that a taxpayer should not be allowed to deduct losses from sales of property between family members because such transactions are often conducted at less than fair market value and can easily be manipulated for tax purposes. In his view, allowing these deductions would open up opportunities for abuse and undermine the integrity of the tax system. Furthermore, he contended that Congress did not intend to allow such deductions when it enacted relevant provisions in 1918 or amended them in 1921 and 1924. Therefore, he believed that interpreting these laws as permitting intra-family transaction deductions was contrary to their legislative intent.