Texas Finance Code - FIN § 95.102. Pledge of Joint Account

(a) Unless the terms of the account provide otherwise, a person on whose signature money may be withdrawn from a deposit account in the names of two or more persons may, by a signed pledge, pledge and transfer to the savings bank or federal savings bank all or part of the account.

(b) A pledge made under Subsection (a) does not sever or terminate the joint and survivorship ownership of the account.