; and (viii) such other activities as shall be determined by the Secretary. (E) Safe harbor for determining substantial contribution (i) In general A person which has economic risk of loss with respect to greater than 50 percent of the direct material costs necessary to the manufacture, production, growth, or extraction of the qualifying production in whole or in significant part within the United States shall be deemed for purposes of subparagraph (A) to make a substantial contribution through the activities of its employees within the United States to the manufacture, production, growth, or extraction of such qualifying production property. (ii) Economic risk of loss For purposes of this subparagraph, a person has economic risk of loss if such person bears the ultimate economic responsibility for the direct material cost. The following factors shall not affect the determination of economic risk of loss: (I) Contractual requirements to insure the direct materials. (II) Contractual liability for breach of performance. (iii) Direct material cost For purposes of this subparagraph, the term direct material cost includes the cost of materials that become an integral part of qualifying production property and materials that are consumed in the ordinary course of production and that can be identified or associated with particular units or groups of units of property produced. . (b) Effective date (1) In general The amendments made by this section shall apply to taxable years beginning after the date of the enactment of this Act. (2) Election for retroactive application If all of the persons entering into a written agreement described in section 199(d)(10)(B) of the Internal Revenue Code of 1986 (as amended by this Act) elect to have this paragraph apply to taxable years beginning on or before the date of the enactment of this Act and can demonstrate, by providing copies of timely filed tax returns (including amended returns) or otherwise, that only one person claimed the deduction under section 199 of such Code in such