The tax imposed by section 4371 shall not apply to—

((1)) ** Effectively connected items** Any amount which is effectively connected with the conduct of a trade or business within the United States unless such amount is exempt from the application of section 882(a) pursuant to a treaty obligation of the United States.

((2)) ** Indemnity bond** Any indemnity bond required to be filed by any person to secure payment of any pension, allowance, allotment, relief, or insurance by the United States, or to secure a duplicate for, or the payment of, any bond, note, certificate of indebtedness, war-saving certificate, warrant or check, issued by the United States.