Was interest paid on federal tax deficiencies subject to California's historical corporate interest-deduction limitations?

Plain-English summary

California Legal Ruling 59 held that interest on federal tax deficiencies was subject to the historical corporate interest-deduction limits in former section 24344.

The ruling treated deficiency interest like interest on borrowed money. By retaining tax that should have been paid earlier, the taxpayer effectively used extra capital until the government assessed the deficiency.

FTB also noted that the underlying federal liability might relate partly to income that was not included in California's tax measure, supporting a limitation rather than an unrestricted deduction.

Why deficiency interest resembled borrowing

The ruling used the definition of interest as compensation for the use or forbearance of money.

Federal deficiency interest compensated the government for either:

• the taxpayer's use of money that should have been paid earlier; or
• the government's forbearance from demanding the money until additional assessment.

During that period, the taxpayer possessed capital beyond what it owned outright, much as it would after borrowing funds.

Why the deduction was limited

Because deficiency interest resembled borrowing interest, FTB concluded that both should receive the same statutory treatment.

The ruling gave an additional reason: federal taxable income could include items not included in California's franchise-tax measure. An unrestricted deduction for interest connected with that broader federal liability could reduce California income even though the related income was absent from the California base.

Former section 24344 supplied the required limitation.

What this means for you

Corporate taxpayers

Under the historical ruling, federal deficiency interest was not automatically deductible in full for California franchise-tax purposes.

Tax directors and controllers

Interest arising from an audit adjustment had to be analyzed under the general corporate interest-limitation provision, not treated as a separate unlimited tax expense.

Accountants and tax professionals

Identify the type of interest, the period it accrued, the underlying federal adjustments, related California tax-base differences, and every current limitation or allocation rule before claiming a deduction.

Common questions

Q: Was federal deficiency interest deductible without limitation?

A: No.

Q: Why did FTB compare it with borrowing?

A: The taxpayer retained money that should have been paid to the government and had the use of that capital during the delay.

Q: Did the ruling deny every deduction?

A: No. It held that the deduction was subject to former section 24344's limitations.

Q: Why did excluded income matter?

A: The federal deficiency could relate partly to income not included in California's tax measure, making an unrestricted California deduction inappropriate under the ruling.

Q: Does this page state current interest-limitation law?

A: No. It explains a 1958 ruling under a former statute.

Citations and references

• Former Cal. Rev. & Tax. Code § 24344
• Deputy v. du Pont, 308 U.S. 488

Source

• Landing page: California FTB Legal Rulings
• Official HTML: Legal Ruling 59

Original ruling text

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Legal Ruling 1958-59

California Franchise Tax Board
Legal Ruling No. 059

June 27, 1958

Interest: Federal Tax Deficiencies

The deduction of interest on Federal tax deficiencies is subject to the limitations set by section 24344 of the Bank and Corporation Tax Law.

Advice is requested as to whether the deduction of interest on Federal tax deficiencies is subject to the limitations set by section 24344 of Bank and Corporation Tax Law.

Interest on tax deficiencies is sufficiently similar to interest on borrowing so that like treatment under the statute is justified. Interest means "compensation for the use or forbearance of money." Deputy v du Pont, 308 U.S. 488. Thus, interest on tax deficiencies is compensation for the use of money which should have been paid earlier to the government, or for the forbearance of the government to demand such money until the additional assessment was made. For the period during which such money was retained, the taxpayer was possessed of capital in excess of that which it owned outright, just as if it had borrowed such amount of money for such period. Further reason for not allowing interest on taxes to be deducted free of any limitation is that the federal income tax liability upon which the interest accrued may be related in part, at least, to items of income no part of which was included in the measure of the California tax. Thus, a limitation is called for and it is provided for in section 24344.

Last updated: 09/24/2025