such person holds (directly or indirectly) a disqualified interest with respect to such entity, and (C) the value of such interest (or payments thereunder) is substantially related to the amount of income or gain (whether or not realized) from the assets with respect to which the investment management services are performed, any income or gain with respect to such interest shall be treated as ordinary income. Rules similar to the rules of subsections (a)(5) and (d) shall apply for purposes of this subsection. (2) Definitions For purposes of this subsection— (A) Disqualified interest (i) In general The term disqualified interest means, with respect to any investment entity— (I) any interest in such entity other than indebtedness, (II) convertible or contingent debt of such entity, (III) any option or other right to acquire property described in subclause (I) or (II), and (IV) any derivative instrument entered into (directly or indirectly) with such entity or any investor in such entity. (ii) Exceptions Such term shall not include— (I) a partnership interest, (II) except as provided by the Secretary, any interest in a taxable corporation, and (III) except as provided by the Secretary, stock in an S corporation. (B) Taxable corporation The term taxable corporation means— (i) a domestic C corporation, or (ii) a foreign corporation substantially all of the income of which is— (I) effectively connected with the conduct of a trade or business in the United States, or (II) subject to a comprehensive foreign income tax (as defined in section 457A(d)(2)). (C) Investment management services The term investment management services means a substantial quantity of any of the services described in subsection (c)(2). (D) Investment entity The term investment entity means any entity which, if it were a partnership, would be an investment partnership. (f) Exception for domestic C corporations Except as otherwise provided by the Secretary, in the case of a domestic C corporation— (1) subsections (a) and (b) shall not apply to any