---
documentId: DBIS-SETTLEMENT-RULEBOOK
title: DBIS Settlement Rulebook (HYBX / OMNL evidence)
version: "1.0"
status: operational-reference
relatedSettlementRef: HYBX-BATCH-001
relatedCycleId: DBIS-SET-HYBX-20260317-001
network: DBIS Mainnet (ChainID 138)
companionDocuments:
  - DBIS_RAIL_RULEBOOK_V1.md
  - DBIS_RAIL_TECHNICAL_SPEC_V1.md
lastReviewed: "2026-03-17"
---

# DBIS Settlement Rulebook

**Purpose:** Define settlement batch evidence, netting semantics, and **ledger row canonicalisation** used for Merkle proofs and regulatory packages (e.g. HYBX-BATCH-001).

## 1. Scope

- Applies to **DBIS clearing cycles** that settle through **OMNL** books (M1 liabilities, interoffice due-to/due-from).
- Cross-references [DBIS Rail Rulebook v1](DBIS_RAIL_RULEBOOK_V1.md) for good funds, finality, and rail policy.

## 2. Batch identity

| Field | Description |
|--------|-------------|
| `settlementBatch` | Batch identifier (e.g. `HYBX-BATCH-001`). |
| `settlementCycle` | Clearing cycle id (e.g. `DBIS-SET-HYBX-20260317-001`). |
| `valueDate` | Business value date (UTC date string). |

## 3. Netting report

Multilateral net positions are reported per participant. For HYBX-BATCH-001 the beneficiary receives the net **credit** in USD; liquidity provider shows offsetting **debit** on OMNL; system net is zero.

## 4. Annex B — Canonical line for Merkle leaves (CSV)

**Input file:** UTF-8 CSV, LF line endings, header row present.

**Leaf input:** Each **complete logical line** of the file (from first byte of the line through the line terminator excluded from hash input per generator: hash is `SHA-256(UTF-8 bytes of the line string without trailing newline on that line)`).

**Ordering:** Leaves are taken in **file order** (top to bottom), including the header row as the first leaf.

**Root:** Binary Merkle tree over leaf digests: `H(left || right)` with SHA-256; if odd count at a level, duplicate last node.

**Verification:** Recompute leaves from the same CSV bytes, rebuild tree, compare root to published `merkle_root_HYBX-BATCH-001.txt`.

## 5. Evidence retention

Submitting institutions retain: CSV, Merkle log, generation tooling identity, and audit manifest binding file hashes to `HASH_NOTARIZATION_ANCHOR.txt` per package build procedure.