Commissioner v. Idaho Power Co.

1974-06-24

Headline: Tax depreciation limits upheld: Court reverses appeals court and rules equipment used to build a company’s own facilities must be capitalized and recovered over the constructed assets’ useful life, affecting self‑builders.

Holding: The Court held that depreciation on equipment used to construct a taxpayer’s own capital facilities is not deductible when incurred and must be capitalized and recovered over the life of the constructed assets.

Real World Impact:

Stops immediate tax deductions for equipment used in a company’s self-construction.
Requires adding construction-related depreciation to the new asset’s basis.
Equalizes tax treatment between self‑building firms and those hiring contractors.

Topics: tax law, business depreciation, capitalization rules, construction accounting

Summary

Background

Idaho Power Company, a public utility, used its own trucks and equipment to build transmission and distribution facilities in 1962 and 1963. On its corporate books the company capitalized the portion of equipment depreciation used in construction, but for federal income tax returns it deducted that depreciation immediately. The Commissioner of Internal Revenue disallowed the tax deduction. The Tax Court followed an earlier Court of Claims decision and sided with the Commissioner, but the Ninth Circuit reversed. The Supreme Court agreed to resolve the conflict.

Reasoning

The Court asked whether depreciation for equipment used to construct a capital asset should be deducted immediately or added to the cost of the asset and written off over the asset’s longer life. The majority reasoned that construction-related costs do not match current income and therefore should be treated as part of the cost of acquiring the new asset. The Court relied on accepted accounting practice, tax principles requiring capitalization of acquisition costs, parity with taxpayers who hire contractors, administrative rulings, and the priority language in the tax code that places the capitalization rule above the general depreciation deduction. The Court therefore ruled for the Commissioner: the construction-related depreciation must be capitalized and recovered over the useful life of the facilities built.

Real world impact

The decision forces companies that build their own facilities to add construction-related equipment depreciation to the asset basis and depreciate it over the long life of the new facilities. That changes when tax deductions occur and equalizes treatment between firms that self‑construct and those using contractors.

Dissents or concurrances

Justice Douglas dissented, arguing depreciation is not an "amount paid out" and should be deductible now; he would have left the Ninth Circuit ruling intact.