(9) Deferral not available for passive assets (A) In general For purposes of subsection (a)(1) and determining the closely held business amount (but not for purposes of subsection (g)), the value of any interest in a closely held business shall not include the value of that portion of such interest which is attributable to passive assets held by the business. (B) Passive asset defined For purposes of this paragraph— (i) In general The term “passive asset” means any asset other than an asset used in carrying on a trade or business. (ii) Stock treated as passive asset The term “passive asset” includes any stock in another corporation unless— (I) such stock is treated as held by the decedent by reason of an election under paragraph (8), and (II) such stock qualified under subsection (a)(1). (iii) Exception for active corporations If— (I) a corporation owns 20 percent or more in value of the voting stock of another corporation, or such other corporation has 45 or fewer shareholders, and (II) 80 percent or more of the value of the assets of each such corporation is attributable to assets used in carrying on a trade or business, then such corporations shall be treated as 1 corporation for purposes of clause (ii). For purposes of applying subclause (II) to the corporation holding the stock of the other corporation, such stock shall not be taken into account.