Cap Table Dilution (Simple) implementation

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-clean

Evidence ID

t5-019

Effect

Computation or source lookup only

Input and validation requirements

A zero pre-money valuation makes price_per_share equal to zero, so new_shares requires division by zero and the specification provides no explicit validation behavior. The option-pool percentage also has a material convention ambiguity: treating it as a post-money fully diluted target differs from treating it as a percentage of pre-round shares.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

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

{
  "inputs": {
    "pre_round_cap_table": {
      "Alice": 600000,
      "Bob": 400000
    },
    "raise_amount_usd": 1000000,
    "pre_money_valuation_usd": 5000000,
    "new_option_pool_pct_post_round": 0.1
  },
  "expected_outputs": {
    "price_per_share_usd": 5,
    "new_shares": 200000,
    "option_pool_shares": 133333.333333,
    "post_round_cap_table_pct": {
      "Alice": 45,
      "Bob": 30,
      "New investor": 15,
      "Option pool": 10
    },
    "dilution_pct_points": {
      "Alice": 15,
      "Bob": 10
    },
    "relative_dilution_pct": {
      "Alice": 25,
      "Bob": 25
    }
  },
  "working": "Pre-round shares = 600,000 + 400,000 = 1,000,000. Price/share = $5,000,000 / 1,000,000 = $5. New shares = $1,000,000 / $5 = 200,000. Let pool shares = x. 10% = x / (1,000,000 + 200,000 + x). Therefore x = 0.10 × (1,200,000 + x); x = 120,000 + 0.10x; 0.90x = 120,000; x = 133,333.333333. Total post-round shares = 1,000,000 + 200,000 + 133,333.333333 = 1,333,333.333333. Alice = 600,000 / 1,333,333.333333 = 45%. Bob = 400,000 / 1,333,333.333333 = 30%. Investor = 200,000 / 1,333,333.333333 = 15%. Pool = 133,333.333333 / 1,333,333.333333 = 10%. Alice dilution = 60% - 45% = 15 percentage points; relative dilution = 15% / 60% = 25%. Bob dilution = 40% - 30% = 10 percentage points; relative dilution = 10% / 40% = 25%."
}

Other records

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