6 Del. C. § 9-314: Perfection by control.

(a) Perfection by control. — A security interest in controllable accounts, controllable electronic records, controllable payment intangibles, deposit accounts, electronic documents, electronic money, investment property, or letter-of-credit rights may be perfected by control of the collateral under Section 7-106, 9-104, 9-105A, 9-106, 9-107, or 9-107A.

(b) Specified collateral: time of perfection by control; continuation of perfection. — A security interest in controllable accounts, controllable electronic records, controllable payment intangibles, deposit accounts, electronic documents, electronic money, or letter-of-credit rights is perfected by control under Section 7-106, 9-104, 9-105A, 9-107, or 9-107A not earlier than the time 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 Section 9-106 not earlier than the time the secured party obtains control and remains perfected by control until:

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

(2) one 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.