Tenn. Code Ann. § 47-9-314: Perfection by control.

(a) Perfection by control. A security interest in investment property, deposit accounts, letter-of-credit rights, electronic chattel paper, or electronic documents may be perfected by control of the collateral under § 47-7-106, § 47-9-104, § 47-9-105, § 47-9-106, or § 47-9-107.

(b) Specified collateral: time of perfection by control; continuation of perfection. A security interest in deposit accounts, electronic chattel paper, letter-of-credit rights, or electronic documents is perfected by control under § 47-7-106, § 47-9-104, § 47-9-105, or § 47-9-107 when the secured party obtains control and remains perfected by control only while the secured party retains control.

(c) Investment property: time of perfection by control; continuation of perfection. A security interest in investment property is perfected by control under § 47-9-106 from the time the secured party obtains control and remains perfected by control until:

(1) the secured party does not have control; and

(2) one (1) of the following occurs:

(A) if the collateral is a certificated security, the debtor has or acquires possession of the security certificate;

(B) if the collateral is an uncertificated security, the issuer has registered or registers the debtor as the registered owner; or

(C) if the collateral is a security entitlement, the debtor is or becomes the entitlement holder.