(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 or flood insurance companies exclusively issuing perpetual policies or whose principal business is the issuance of policies for which the premium deposits are the same regardless of the length of the term for which the policies are written, are subject to the tax imposed by section 831 if the unabsorbed portion of such premium deposits not required for losses, expenses or reserves is returned or credited to the policyholder on cancellation or expiration of the policy. For purposes of section 831 and this section, in the case of a mutual flood insurance company, the premium deposits will be considered to be the same if the payment of a premium increases the total insurance under the policy in an amount equal to the amount of such premium and the omission of any annual premium does not result in the reduction or suspension of coverage under the policy. As used in this section and section 832 and the regulations thereunder, 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.