BridgeLine · Tools · Investor · Dilution Modeler
Equity Dilution Modeler
Model ownership dilution across Pre-Seed through Series C with biotech-specific round sizes, option pool expansion, liquidation preferences, and exit proceeds analysis
Beta Testing. This tool is under active development. Results are estimates based on industry benchmarks and should not substitute for professional financial or strategic advice. We welcome feedback at info@bridgelinetranslational.com.
Choose your modality
Round sizes and valuations pre-loaded from industry benchmarks. Edit any value below.
General biotech defaults. Adjust based on your specific modality and stage.
Funding Rounds
Pre-Seed$1.0M at $5.0M pre
Allocates extra investor shares equal to (coverage % of round / price). Typical 5-20% on bridge / extension rounds.
Founders sell existing shares into the round at the round price. Non-dilutive to other holders; founders lose ownership pct.
Seed$4.0M at $12.0M pre
Allocates extra investor shares equal to (coverage % of round / price). Typical 5-20% on bridge / extension rounds.
Founders sell existing shares into the round at the round price. Non-dilutive to other holders; founders lose ownership pct.
Series A$25.0M at $55.0M pre
Allocates extra investor shares equal to (coverage % of round / price). Typical 5-20% on bridge / extension rounds.
Founders sell existing shares into the round at the round price. Non-dilutive to other holders; founders lose ownership pct.
Series B$60.0M at $200.0M pre
Allocates extra investor shares equal to (coverage % of round / price). Typical 5-20% on bridge / extension rounds.
Founders sell existing shares into the round at the round price. Non-dilutive to other holders; founders lose ownership pct.
Series C
Allocates extra investor shares equal to (coverage % of round / price). Typical 5-20% on bridge / extension rounds.
Founders sell existing shares into the round at the round price. Non-dilutive to other holders; founders lose ownership pct.
Broad-based weighted-average is the most common VC-negotiated protection. Full ratchet is aggressive and rarely granted to founders at Series A or later.
After 4 rounds
From founding
Ownership Evolution
Cap Table (Final)
| Stakeholder | Shares | Ownership | Invested |
|---|---|---|---|
Founders | 10,000,000 | 24.9% | - |
Option Pool | 4,812,882 | 12.0% | - |
Pre-Seed | 2,127,660 | 5.3% | $1.0M |
Seed | 4,664,485 | 11.6% | $4.0M |
Series A | 9,246,776 | 23.1% | $25.0M |
Series B | 9,255,541 | 23.1% | $60.0M |
Round-by-Round Summary
| Round | Post-Money | Price/Share | Investor % | Pool % | Founder % |
|---|---|---|---|---|---|
| Founding | - | - | - | 0.0% | 100.0% |
| Pre-Seed | $6.0M | $0.4700 | 16.7% | 5.0% | 78.3% |
| Seed | $16.0M | $0.8575 | 25.0% | 10.0% | 53.6% |
| Series A | $80.0M | $2.7036 | 31.3% | 12.0% | 33.8% |
| Series B | $260.0M | $6.4826 | 23.1% | 12.0% | 24.9% |
Exit Proceeds Analysis
Based on last round post-money of $260.0M. Accounts for non-participating liquidation preferences.
| Exit Value | Founders | Pre-Seed | Seed | Series A | Series B |
|---|---|---|---|---|---|
| $130.0M (0.5x) | $26.9M | $5.7M | $12.5M | $24.9M | $60.0M |
| $260.0M (1x) | $73.7M | $15.7M | $34.4M | $68.1M | $68.2M |
| $520.0M (2x) | $147.3M | $31.3M | $68.7M | $136.2M | $136.4M |
| $780.0M (3x) | $221.0M | $47.0M | $103.1M | $204.4M | $204.5M |
| $1.3B (5x) | $368.3M | $78.4M | $171.8M | $340.6M | $340.9M |
| $2.6B (10x) | $736.7M | $156.7M | $343.6M | $681.2M | $681.8M |
What This Means
At 24.9% founder ownership, you are in the typical range for biotech founders through Series B. Focus on hitting clinical milestones that drive significant step-ups in valuation to protect your economics.
Biotech founders typically retain 15-30% through Series B. Gene therapy and cell therapy founders often see more dilution due to higher capital requirements. Negotiation leverage comes from clinical data, IP strength, and competitive dynamics.
Methodology & assumptions
Option pool expansion is modeled as pre-money dilution. The pool is expanded before pricing each round so that post-money pool meets the target percentage. This follows standard VC convention.
Price per share = pre-money valuation / total shares (after pool expansion, before new investor shares).
Liquidation preferences are modeled as senior preferred. Non-participating investors choose the higher of their preference or pro-rata common conversion. Participating investors receive their preference plus pro-rata share of remaining proceeds.
Round sizes and valuations are based on 2023-2025 biotech financing data from PitchBook, BioCentury, and Endpoints News analysis of venture rounds by modality.
This tool provides estimates for planning purposes only. Actual terms vary by company, market conditions, and negotiation. Consult legal and financial advisors for cap table and term sheet decisions.
Continue your analysis by handing off to the next tool in the workflow. Your program data carries forward automatically.
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