26 U.S.C. section 501(c)(15)
(A) Insurance companies (as defined in section 816 (a)) other than life (including interinsurers and reciprocal underwriters) if --
(I) the gross receipts for the taxable year do not exceed $600,000, and
(II) more than 50 percent of such gross receipts consist of premiums, or
(ii) in the case of a mutual insurance company--
(I) the gross receipts of which for the taxable year do not exceed $150,000, and
(II) more than 35 percent of such gross receipts consist of premiums.
Clause (ii) shall not apply to a company if any employee of the company, or a member of the employee's family (as defined in section 2032A (e)(2)), is an employee of another company exempt from taxation by reason of this paragraph (or would be so exempt but for this sentence).
(B) For purposes of subparagraph (A), in determining whether any company or association is described in subparagraph (A), such company or association shall be treated as receiving during the taxable year amounts described in subparagraph (A) which are received during such year by all other companies or associations which are members of the same controlled group as the insurance company or association for which the determination is being made.
(C) For purposes of subparagraph (B), the term "controlled group" has the meaning given such term by section 831 (b)(2)(B)(ii), except that in applying section 831 (b)(2)(B)(ii) for purposes of this subparagraph, subparagraphs (B) and (C) of section 1563 (b)(2) shall be disregarded.