15 U.S. Code § 63 - Acquisition of stock of export trade corporation
Nothing contained in section 18 of this title shall be construed to forbid the acquisition or ownership by any corporation of the whole or any part of the stock or other capital of any corporation organized solely for the purpose of engaging in export trade, and actually engaged solely in such export trade, unless the effect of such acquisition or ownership may be to restrain trade or substantially lessen competition within the United States.
Source(Apr. 10, 1918, ch. 50, § 3,40 Stat. 517.)