ISBP 745 Section B — Draft Maturity Date Calculation and Its Three Deterministic Failure Modes

Introduction

A documentary credit available by acceptance or deferred payment hinges on one deceptively simple arithmetic operation: computing the maturity date from a reference date on a transport document. Banks, beneficiaries, and applicants routinely assume this calculation is mechanical. It is not. ISBP 745 Section B encodes three distinct date-selection rules for transshipment scenarios, and misapplying any one of them produces a maturity date that is, in a binary sense, wrong. The result is either a premature payment demand or a late payment — both of which truncate the drawee bank's obligation and isolate the presenter from recourse.

The maturity date is the date on which the drawee bank's deferred payment undertaking or acceptance obligation crystallizes. Miscalculate it, and the entire payment architecture collapses into a dispute over whether the draft was drawn "at maturity" or whether the bank simply refused to pay on a date that never should have been the due date.

Failure Mode Analysis

Failure Mode 1: Applying the Wrong Date-Selection Rule to Transshipment

ISBP 745 paragraph B2(e)(i) addresses goods unloaded and reloaded from one vessel to another (transshipment), with more than one dated on-board notation, where each shipment was effected from a port within a permitted geographical area:

The earliest of these dates is to be used for the calculation of the maturity date.

The example in the standard is precise: a credit requires shipment from any European port, the bill of lading evidences on-board vessel "A" from Dublin on 14 May, with transshipment on-board vessel "B" from Rotterdam on 16 May. The draft must reflect 60 days after 14 May (the earliest date), not 16 May.

The failure mode is systematic: practitioners habitually default to the latest on-board date, treating it as the "shipment date." This is a mutation of the actual rule. The earliest date applies because the goods were already in transit from the first port — the later notation merely evidences transshipment, not a separate shipment event. Selecting the latest date truncates the maturity period by the exact number of days between the two on-board notations, producing a payment obligation that matures before the correct date.

Failure Mode 2: Single Vessel, Multiple Ports — The Inverse Rule

ISBP 745 paragraph B2(e)(ii) addresses a different factual scenario: goods loaded on the same vessel from more than one port within a permitted geographical area, with more than one dated on-board notation:

The latest of these dates is to be used for the calculation of the maturity date.

The example: a credit requires shipment from any European port, the bill of lading evidences part of the goods loaded on board vessel "A" from Dublin on 14 May and the remainder on board the same vessel from Rotterdam on 16 May. The draft must reflect 60 days after 16 May (the latest date).

This is the inverse of B2(e)(i). The rationale is mechanical: when goods are loaded from multiple ports on the same vessel, the shipment is not complete until the last port loading occurs. The latest date is the true completion of the shipment transaction. Applying the earliest date here would be a failure mode that truncates the maturity period — the presenter would demand payment before the shipment was actually completed.

The operative distinction between B2(e)(i) and B2(e)(ii) is whether the goods move between vessels (transshipment) or remain on the same vessel. Misidentifying the factual scenario produces the wrong rule and a deterministic error in the maturity date.

Failure Mode 3: Multiple Sets of Bills of Lading Under One Draft

ISBP 745 paragraph B2(e)(iii) addresses the scenario where more than one set of bills of lading is presented under one draft:

The on board date of the latest bill of lading will be used for the calculation of the maturity date.

This rule is straightforward in isolation but compounds the risk when combined with B2(e)(i) or B2(e)(ii). A presenter must first determine whether each bill of lading involves transshipment (B2(e)(i)) or same-vessel loading (B2(e)(ii)), compute the relevant date for each bill of lading, and then apply B2(e)(iii) to select the latest among those computed dates.

The failure mode here is a cascading error: selecting the wrong date for one bill of lading under B2(e)(i) or B2(e)(ii), then feeding that erroneous date into the B2(e)(iii) selection. The compound error can shift the maturity date by weeks.

Deterministic Resolution Architecture

1. Isolate the factual scenario before computing any date. Determine: (a) is there transshipment between vessels? (b) is there loading from multiple ports on the same vessel? (c) are there multiple sets of bills of lading? These are factual questions, not legal interpretations.

2. Apply the correct sub-paragraph in strict sequence. B2(e)(i) for transshipment (earliest date). B2(e)(ii) for same-vessel multiple-port loading (latest date). B2(e)(iii) for multiple bills of lading (latest bill of lading date). Do not blend rules.

3. Verify the "from" and "after" exclusion under UCP 600 Article 3. The reference date is excluded from the count. "60 days after 14 May" means the first day of the count is 15 May, and maturity falls on 13 July.

4. Confirm the maturity date is a banking day under ISBP 745 paragraph B7. If the computed maturity date falls on a non-banking day, payment is due on the first following banking day. Delays in remittance — including grace days — are not added to the due date.

5. Validate against the credit terms under ISBP 745 paragraph B4. The maturity date stated on the draft must reflect the terms of the credit. If the draft states a fixed date that does not match the computed maturity date, the draft is discrepant.

6. Check drawee bank confirmation under ISBP 745 paragraph B5(c). The drawee bank is to advise or confirm the maturity date to the presenter. If the drawee bank's confirmed date differs from the presenter's computation, escalate before the maturity date — do not wait for the payment obligation to crystallize.

7. Document the computation in the presentation record. Attach a schedule showing: the reference date selected, the sub-paragraph applied, the arithmetic, and the resulting maturity date. This creates a deterministic audit trail that isolates any future dispute to a single factual or legal question.

Conclusion

The maturity date is not a clerical detail. It is the date on which a bank's irrevocable undertaking to pay becomes due. ISBP 745 Section B provides three distinct date-selection rules for multi-date transport documents, and each rule produces a different maturity date from the same set of facts. The rules are deterministic — there is no discretion, no "reasonable banker" standard, and no tolerance for approximate calculation.

The systemic risk is that practitioners treat maturity date calculation as a single rule (always the latest date, or always the on-board date) when in fact the standard requires case-by-case factual analysis. Isolate the scenario, apply the correct sub-paragraph, and verify the arithmetic against UCP 600 Article 3's exclusion principle. The maturity date is either correct or it is not. There is no middle ground.

FAQ

Q1: If a bill of lading shows an on-board date of 1 May but was issued on 5 May, which date is used for maturity calculation?

A: Per ISBP 745 paragraph B2(c), the on-board date is deemed to be the bill of lading date even when the on-board date is prior to or later than the date of issuance. So 1 May (the on-board date) is the reference date. This principle is absolute — the issuance date is irrelevant for maturity calculation.

Q2: A credit requires "90 days after bill of lading date." The bill of lading evidences transshipment from Hamburg on 10 June and Singapore on 15 June. Which date starts the 90-day count?

A: Per ISBP 745 paragraph B2(e)(i), the earliest date (10 June) is used. The count commences on 11 June (UCP 600 Article 3 excludes the reference date), and maturity falls on 9 September.

Q3: Can the beneficiary draw a draft for a maturity date that differs from the computed date if the credit allows it?

A: No. ISBP 745 paragraph B4 states that the maturity date must reflect the terms of the credit. ISBP 745 paragraph B2(a) requires the tenor to be in accordance with the credit terms. A draft stating an incorrect maturity date is discrepant under Article 14.

Q4: What happens if the computed maturity date falls on a Saturday and the drawee bank is closed?

A: Per ISBP 745 paragraph B7, payment is due on the first banking day following the due date. The due date remains the Saturday — the obligation simply shifts to Monday (or the next business day). Grace days or remittance delays are not added.

Q5: If multiple sets of bills of lading are presented, and one shows transshipment (B2(e)(i)) while another shows same-vessel loading (B2(e)(ii)), how is the maturity date determined?

A: Apply B2(e)(i) or B2(e)(ii) independently to each bill of lading to determine the relevant date for each. Then apply B2(e)(iii) and select the latest among those computed dates. This is a two-step process — do not skip the per-bill-of-lading analysis.