1. Enter starting ownership
Use the founder’s stake at the beginning of the period you want to evaluate.
2. Enter current ownership
Use the latest comparable fully diluted percentage.
3. Check the retention rate
This shows current ownership as a share of the original ownership.
4. Review both loss measures
Percentage-point decline and relative reduction answer different questions.
5. Keep the basis consistent
Do not mix basic-share ownership with fully diluted ownership.
Where:
Assumptions: Both percentages must use the same cap-table definition. The metric does not distinguish dilution from voluntary transfers or model voting rights.
Original founder ownership retained.
Use the result as a planning estimate based on the assumptions above.
Given: A founder owned 75% at incorporation and owns 42% after several rounds.
Calculation: Retention rate: 42 ÷ 75 × 100 = 56%. Percentage-point decline: 75% − 42% = 33 points. Relative reduction: 33 ÷ 75 × 100 = 44%.
Result: The founder has retained 56% of the original stake and given up 44% of it on a relative basis.
It can if the founder acquires additional shares, but this implementation allows current ownership up to 100% and may show a rate above 100% when the starting stake was lower.
Current ownership is the stake today. Retention compares that stake with the founder’s own starting position.
Use the same convention at both dates. Fully diluted comparisons often include all outstanding founder shares subject to repurchase.
No. Dilution may accompany financing that increases company value, so retention should be considered with valuation and control.
No. It summarizes the change between two points; use a dilution-by-round model for attribution.