Section 363.40 - How are payments of principal and interest made?(a)Payment of a savings bond that has reached final maturity. We will purchase a zero-percent certificate of indebtedness in your TreasuryDirect ® account using the proceeds of a matured savings bond.(b)Payments of interest and principal (except a savings bond that has reached final maturity).(1) We provide two methods of receiving payments of principal and interest:(i) Payment to your account at a financial institution by the ACH method, or(ii) Payment to your TreasuryDirect account to purchase a zero-percent certificate of indebtedness.(2) You may select different payment destinations for principal and interest for a marketable Treasury security. You may change your payment destination at any time, unless the security is in the closed book period. (See § 363.210 .)(3) If we are unable to deliver a payment, we will use the payment to purchase a zero-percent certificate of indebtedness in your TreasuryDirect account.70 FR 57443, Sept. 30, 2005