Every such corporation shall be authorized and empowered to subscribe for, purchase, hold, pledge and sell the stock of a corporation organized and existing under the laws of the state of Missouri, or under any act of Congress of the United States, for the purpose of developing and maintaining a stable and open market for foreign and domestic bills of exchange, notes, acceptances, and other evidences of debt originating in connection with foreign and domestic trade, by the purchase, investment in, and sale thereof, or for the purpose of engaging in international or foreign banking or other international or foreign financial operations, or in banking or other financial operations in a dependency or insular possessions of the United States, either directly or through the agency, ownership, or control of local institutions in foreign countries, or in such dependencies or insular possessions as provided by this section, and to act when required by the Secretary of the Treasury as fiscal agents of the United States; provided, that the investment of a bank in the stock of such a corporation shall not exceed ten percent of its capital and surplus.