A standby letter of credit is governed by whatever rules the standby says govern it. Three ICC rule sets appear in practice, they are not interchangeable, and the choice has practical consequences for how a drawing is examined and how quickly it is paid.
UCP 600, the Uniform Customs and Practice for Documentary Credits, was written for commercial documentary credits — the credits used to pay for shipments against bills of lading, invoices and insurance documents. Standbys were historically issued under UCP because it was the only ruleset available, and it can still be used, but much of it is about documents a standby never calls for. Applying it to a standby means applying rules on transport documents, insurance and shipment dates to an instrument where none of that arises.
ISP98, the International Standby Practices, was written specifically for standby letters of credit and is the natural default. It starts from the premise that the instrument secures an obligation rather than pays for goods, and it addresses the situations standbys actually produce: multiple and partial drawings, automatic extension, transfer by operation of law, syndicated and counter standbys, and the handling of a demand that is presented near expiry.
URDG 758, the Uniform Rules for Demand Guarantees, is the ICC ruleset for demand guarantees rather than standbys. Where a beneficiary or a tender board requires a guarantee, URDG 758 is the right framework and the instrument is a guarantee, not a standby. Mixing the two — a standby that recites URDG, or a guarantee that recites ISP98 — creates avoidable argument at the moment of drawing.
What actually changes between them is worth knowing. Examination periods differ: UCP 600 gives the issuer a maximum of five banking days following presentation to examine and decide, while ISP98 works on a standard of a reasonable time not exceeding a stated number of business days, with a shorter period treated as reasonable where the standby is simple. Notice of dishonour is disciplined under both, but ISP98 sets out expressly what a notice must contain and the consequence of failing to send one. Force majeure is treated more generously to the beneficiary under ISP98, which extends expiry for a stated period where the issuer's place of business is closed for reasons beyond its control, whereas UCP 600 does not extend expiry for an interruption of business. Transfer and assignment are handled in more detail under ISP98, which distinguishes clearly between transfer of drawing rights and assignment of proceeds, and which recognises transfer by operation of law to a successor of the named beneficiary.
The practical advice is short. State the governing rules explicitly in the standby's wording, name one ruleset rather than two, and make sure the ruleset named is the one that matches the instrument being issued. Where the beneficiary's bank has a house preference, it is far cheaper to settle that in the draft wording before issuance than to discover it when a demand is presented.
This is general information on international practice rather than legal advice, and the applicable law of the standby may qualify how the rules operate in a given jurisdiction.