The transferee of a negotiable tangible document of title has a specifically enforceable right to have its transferor supply any necessary endorsement, but the transfer becomes a negotiation only as of the time the endorsement is supplied.
Wis. Stat. § 407.506
Delivery without endorsement; right to compel endorsement
2009 a. 322.
Official source: Wisconsin State Legislature. Reproduced from public-domain Wisconsin statutes; confirm against the official source for the current text. Not legal advice.