Okla. Stat. tit. 6, § 6-412: Signature guaranty

(1) A bank may become guarantor of the genuineness of a

signature.

(2) A bank guaranteeing the signature of a person on any

document warrants to any person relying on such guaranty only that:

(a) the signature is that of the person signing; and

(b) the signer is the holder, or the signer has purported

authority to sign in the name of the holder; provided that if the

holder purports to act as a fiduciary either as "fiduciary" as

defined in this Code or his name is signed by a person purporting to

act on the holder's behalf as a fiduciary, the bank warrants that

such holder or such person so signing as such fiduciary is in fact

the fiduciary he purports to be and warrants that the bank has no

actual knowledge that such fiduciary is committing a breach of his

obligation as such fiduciary in signing such document and that it

has no knowledge of such facts that its action in guaranteeing the

signature amounts to bad faith; and

(c) the signer has legal capacity to sign.

(3) A bank may disclaim in its guaranty all or any part of the

obligations set forth in subsection (2)(b) of this section.