283 U.S. 404 (1931)
Burnet v. Logan is a landmark case in United States tax law, particularly addressing the taxation of realized gains from the sale of stock.
Can a taxpayer be taxed on the future contingent payments received from the sale of stock when the future payments' total value is not ascertainable at the time of the sale?
Under the federal tax principle, a gain must be 'realized' before it can be taxed, meaning there must be a clear economic benefit or measurable value received.
The Supreme Court held that the taxpayer cannot be taxed on the future contingent payments until those payments are actually received and therefore realized.
Burnet v. Logan underscored the critical distinction between realized and unrealized income or gain — a pivotal concept in tax law. It established a precedent that a taxpayer is not liable to pay taxes on income that is speculative and not yet actualized. This case serves as a foundational reference in future interpretations of taxable income, particularly in complex asset sale situations.