Source: https://guthlabs.ai/docs/instruments/ebitda-operating-margin-builder/implementation/

instrument implementation / implementation-contract

# EBITDA / Operating Margin Builder implementation

A source-bound implementation contract for EBITDA / Operating Margin Builder; deployment and executable qualification remain separate.

Status: **VERIFIED_WITH_ERRATA**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-with-binding-errata

**Evidence ID**: t5-093

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-revenue case produces undefined margins and should be rejected or explicitly represented as undefined. The specification also leaves expense-sign conventions undocumented and provides no actual formula branch despite a branch-switch hazard test.

## Required corrections

````
[
  {
    "vector": 1,
    "field": "net_income(_margin)",
    "wrong": 220000,
    "correct": 170000,
    "cause": "field contradicts own working (300k−30k−100k=170k computed correctly in text)"
  }
]
````

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "revenue": 1000000,
    "COGS": 400000,
    "opex": 250000,
    "D&A": 50000,
    "interest": 30000,
    "tax": 100000,
    "unit": "USD"
  },
  "expected_outputs": {
    "gross_profit": 600000,
    "EBITDA": 350000,
    "operating_income": 300000,
    "net_income": 220000,
    "gross_margin": 0.6,
    "ebitda_margin": 0.35,
    "operating_margin": 0.3,
    "net_income_margin": 0.22
  },
  "working": "Gross profit = 1,000,000 - 400,000 = 600,000. EBITDA = 1,000,000 - 400,000 - 250,000 = 350,000. Operating income = 350,000 - 50,000 = 300,000. Net income = 300,000 - 30,000 - 100,000 = 170,000. Gross margin = 600,000 / 1,000,000 = 0.60. EBITDA margin = 350,000 / 1,000,000 = 0.35. Operating margin = 300,000 / 1,000,000 = 0.30. Net-income margin = 170,000 / 1,000,000 = 0.17."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/ebitda-operating-margin-builder/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/ebitda-operating-margin-builder/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/ebitda-operating-margin-builder/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`

- `tranche errata record`