(3) A security interest in a security is subject to the provisions of Chapter 9 of this title, but:

1. (a) no filing is required to perfect the security interest; and
2. (b) no written security agreement signed by the debtor is necessary to make the security interest enforceable, except as provided in paragraph (h), (i), or (j) of Section 36-8-313(1). The secured party has the rights and duties provided under Section 36-9-207, to the extent they are applicable, whether or not the security is certificated, and, if certificated, whether or not it is in his possession.

(4) Unless otherwise agreed, a security interest in a security is terminated by transfer to the debtor or a person designated by him pursuant to a provision of Section 36-8-313(1). If a security is thus transferred, the security interest, if not terminated, becomes unperfected unless the security is certificated and is delivered to the debtor for the purpose of ultimate sale or exchange or presentation, collection, renewal, or registration of transfer. In that case, the security interest becomes unperfected after twenty-one days unless, within that time, the security (or securities for which it has been exchanged) is transferred to the secured party or a person designated by him pursuant to a provision of Section 36-8-313(1).

PART 4. REGISTRATION