(a) The bona fide purchase and sale of securities on a national securities exchange by banking institutions within the United States for the account, and pursuant to the authorization, of nationals of a designated foreign country and the making and receipt of payments, transfers of credit, and transfers of such securities which are necessary incidents of any such purchase or sale are hereby authorized provided the following terms and conditions are complied with:

(1) In the case of the purchase of securities, the securities purchased shall be held in an account in a banking institution within the United States in the name of the national whose account was debited to purchase such securities; and

(2) In the case of the sale of securities, the proceeds of the sale shall be credited to an account in the name of the national for whose account the sale was made and in the banking institution within the United States which held the securities for such national.

(b) This section does not authorize the crediting of the proceeds of the sale of securities held in a blocked account or a subaccount thereof, to a blocked account or subaccount under any name or designation which differs from the name or designation of the specific blocked account or subaccount in which such securities were held.

(c) Securities issued or guaranteed by the Government of the United States or any State, territory, district, county, municipality, or other political subdivision thereof (including agencies and instrumentalities of the foregoing) need not be purchased or sold on a national securities exchange, but purchases or sales of such securities shall be made at market value and pursuant to all other terms and conditions prescribed in this section.