(a) Change of classification or duties
In order to put into force and effect the policy of Congress by this chapter intended, the commission (1) upon request of the President, or (2) upon resolution of either or both Houses of Congress, or (3) upon its own motion, or (4) when in the judgment of the commission there is good and sufficient reason therefor, upon application of any interested party, shall investigate the differences in the costs of production of any domestic article and of any like or similar foreign article. In the course of the investigation the commission shall hold hearings and give reasonable public notice thereof, and shall afford reasonable opportunity for parties interested to be present, to produce evidence, and to be heard at such hearings. The commission shall report to the President the results of the investigation and its findings with respect to such differences in costs of production. If the commission finds it shown by the investigation that the duties expressly fixed by statute do not equalize the differences in the costs of production of the domestic article and the like or similar foreign article when produced in the principal competing country, the commission shall specify in its report such increases or decreases in rates of duty expressly fixed by statute (including any necessary change in classification) as it finds shown by the investigation to be necessary to equalize such differences. In no case shall the total increase or decrease of such rates of duty exceed 50 per centum of the rates expressly fixed by statute.

(b) Repealed. Pub. L. 96–39, title II, §202(a)(2)(A), July 26, 1979, 93 Stat. 202

(c) Proclamation by the President
The President shall by proclamation approve the rates of duty and changes in classification specified in any report of the commission under this section, if in his judgment such rates of duty and changes are shown by such investigation of the commission to be necessary to equalize such differences in costs of production.

(d) Effective date of rates and changes
Commencing thirty days after the date of any presidential proclamation of approval the increased or decreased rates of duty and changes in classification specified in the report of the commission shall take effect.

(e) Ascertainment of differences in costs of production
In ascertaining under this section the differences in costs of production, the commission shall take into consideration, in so far as it finds it practicable:

(1) In the case of a domestic article

(A) The cost of production as hereinafter in this section defined; (B) transportation costs and other costs incident to delivery to the principal market or markets of the United States for the article; and (C) other relevant factors that constitute an advantage or disadvantage in competition.

(2) In the case of a foreign article

(A) The cost of production as hereinafter in this section defined, or, if the commission finds that such cost is not readily ascertainable, the commission may accept as evidence thereof, or as supplemental thereto, the weighted average of the invoice prices or values for a representative period and/or the average wholesale selling price for a representative period (which price shall be that at which the article is freely offered for sale to all purchasers in the principal market or markets of the principal competing country or countries in the ordinary course of trade and in the usual wholesale quantities in such market or markets); (B) transportation costs and other costs incident to delivery to the principal market or markets of the United States for the article; (C) other relevant factors that constitute an advantage or disadvantage in competition, including advantages granted to the foreign producers by a government, person, partnership, corporation, or association in a foreign country.

(f) Modification of changes in duty
Any increased or decreased rate of duty or change in classification which has taken effect as above provided may be modified or terminated in the same manner and subject to the same conditions and limitations (including time of taking effect) as is provided in this section in the case of original increases, decreases, or changes.

(g) Prohibition against transfers from the free list to the dutiable list or from the dutiable list to the free list
Nothing in this section shall be construed to authorize a transfer of an article from the dutiable list to the free list or from the free list to the dutiable list, nor a change in form of duty. Whenever it is provided in any paragraph of Subtitle I of this chapter, or in any amendatory act, that the duty or duties shall not exceed a specified ad valorem rate upon the articles provided for in such paragraph, no rate determined under the provisions of this section upon such articles shall exceed the maximum ad valorem rate so specified.

(h) Definitions
For the purpose of this section—

(1) The term "domestic article" means an article wholly or in part the growth or product of the United States; and the term "foreign article" means an article wholly or in part the growth or product of a foreign country.

(2) The term "United States" includes the several States and Territories and the District of Columbia.

(3) The term "foreign country" means any empire, country, dominion, colony, or protectorate, or any subdivision or subdivisions thereof (other than the United States and its possessions).

(4) The term "cost of production", when applied with respect to either a domestic article or a foreign article, includes, for a period which is representative of conditions in production of the article: (A) The price or cost of materials, labor costs, and other direct charges incurred in the production of the article and in the processes or methods employed in its production; (B) the usual general expenses, including charges for depreciation or depletion which are representative of the equipment and property employed in the production of the article and charges for rent or interest which are representative of the cost of obtaining capital or instruments of production; and (C) the cost of containers and coverings of whatever nature, and other costs, charges, and expenses incident to placing the article in condition packed ready for delivery.

(i) Rules and regulations of President
The President is authorized to make all needful rules and regulations for carrying out his functions under the provisions of this section.

(j) Repealed. Pub. L. 96–39, title II, §202(a)(2)(D), July 26, 1979, 93 Stat. 202

(k) Investigations prior to June 17, 1930
All uncompleted investigations instituted prior to June 17, 1930, under the provisions of sections 154 to 159 ¹ of this title, including investigations in which the President has not proclaimed changes in classification or increases or decreases in rates of duty, shall be dismissed without prejudice; but the information and evidence secured by the commission in any such investigation may be given due consideration in any investigation instituted under the provisions of this section.