Quick search by citation:

22 U.S. Code § 290i–4 - Restrictions

(a) [1] Unless authorized by law, neither the President, nor any person or agency, shall, on behalf of the United States—
(1)
subscribe to additional shares of stock of the Bank;
(2)
vote for or agree to any amendment of the agreement which increases the obligations of the United States, or which changes the purpose or functions of the Bank; or
(3)
make a loan or provide other financing to the Bank, except that funds for technical assistance may be provided to the Bank by a United States agency created pursuant to an Act of Congress which is authorized by law to provide funds to international organizations.