to this subsection) but only if a United States shareholder (determined without regard to this subsection) owns (within the meaning of section 958(a)) stock in such corporation at some time during such taxable year. (4) Treatment of mutual insurance companies In the case of a mutual insurance company— (A) this subsection shall apply, (B) policyholders of such company shall be treated as shareholders, and (C) appropriate adjustments in the application of this subpart shall be made under regulations prescribed by the Secretary. (5) Determination of pro rata share (A) In general The pro rata share determined under this paragraph for any United States shareholder is the lesser of— (i) the amount which would be determined under paragraph (2) of section 951(a) if— (I) only related person insurance income were taken into account, (II) stock owned (within the meaning of section 958(a)) by United States shareholders on the last day of the taxable year were the only stock in the foreign corporation, and (III) only distributions received by United States shareholders were taken into account under subparagraph (B) of such paragraph (2), or (ii) the amount which would be determined under paragraph (2) of section 951(a) if the entire earnings and profits of the foreign corporation for the taxable year were subpart F income. (B) Coordination with other provisions The Secretary shall prescribe regulations providing for such modifications to the provisions of this subpart as may be necessary or appropriate by reason of subparagraph (A). (6) Related person For purposes of this subsection— (A) In general Except as provided in subparagraph (B), the term related person has the meaning given such term by section 954(b). (B) Treatment of certain liability insurance policies In the case of any policy of insurance covering liability arising from services performed as a director, officer, or employee of a corporation or as a partner or employee of a partnership, the person performing such services and the entity for which such services