(a) All insurance companies, other than life or mutual or foreign insurance companies not carrying on an insurance business within the United States, and all mutual marine insurance companies and mutual fire insurance companies exclusively issuing either perpetual policies, or policies for which the sole premium charged is a single deposit which, except for such deduction of underwriting costs as may be provided, is refundable upon cancellation or expiration of the policy, are subject to the tax imposed by section 831. As used in this section and §§1.832-1 and 1.832-2, the term “insurance companies” means only those companies which qualify as insurance companies under the definition provided by paragraph (b) of §1.801-1 and which are subject to the tax imposed by section 831.

(b) All provisions of the Code and of the regulations in this part not inconsistent with the specific provisions of section 831 are applicable to the assessment and collection of the tax imposed by section 831(a), and insurance companies are subject to the same penalties as are provided in the case of returns and payment of income tax by other corporations.

(c) Since section 832 provides that the underwriting and investment exhibit of the annual statement approved by the National Convention of Insurance Commissioners shall be the basis for computing gross income and since the annual statement is rendered on the calendar year basis, the returns under section 831 shall be made on the basis of the calendar year and shall be on Form 1120. Insurance companies are entitled, in computing insurance company taxable income, to the deductions provided in part VIII (section 241 and following), subchapter B, chapter 1 of the Code.

(d) Foreign insurance companies not carrying on an insurance business within the United States are not taxable under section 831 but are taxable as other foreign corporations. See section 881.

(e) Insurance companies are subject to both normal tax and surtax. The normal tax shall be computed as provided in section 11(b) and the surtax shall be computed as provided in section 11(c). For the circumstances under which the $25,000 exemption from surtax for certain taxable years may be disallowed in whole or in part, see section 1551. For alternative tax where the net long-term capital gain for any taxable year exceeds the net short-term capital loss, see section 1201(a) and the regulations thereunder.