Written by — Co-Founder, Expert Sapiens
Reviewed June 2026
Fundraising & Equity
What Is Dilution?
Definition
Dilution is the reduction in an existing shareholder's ownership percentage that happens when a company issues new shares — most commonly during a funding round or when granting an option pool.
If a founder owns 100% of a company with 10 million shares and the company issues 2.5 million new shares to investors, the founder's stake drops to roughly 80% — even though the number of shares they personally hold hasn't changed. Every funding round dilutes existing shareholders unless they have negotiated anti-dilution or pro-rata rights letting them buy additional shares to maintain their percentage.
Dilution compounds across multiple rounds: a founder who owns 100% pre-seed might own 60-70% after seed, 45-55% after Series A, and considerably less by Series C, even without ever selling a share. Expanding the option pool (to hire employees) is itself a dilution event, and VCs frequently negotiate that the pool be created "pre-money" — meaning existing shareholders, not the new investors, absorb that dilution.
Why it matters
Founders who don't model dilution across several future rounds are routinely surprised by how little of the company they own by the time of an exit. A fractional CFO or startup-focused financial advisor can build a cap table model that projects ownership through multiple future raises, so founders can negotiate valuation and option-pool size with the actual long-term impact in view, not just the current round.