Dilution is the quiet arithmetic of venture financing: when a company issues new shares to investors, everyone who already owned a piece owns a smaller fraction of the same pie.
The mechanic
Say you and your co-founder each hold 4,500,000 of a company's 10,000,000 shares — 45 percent each, with 10 percent in an option pool. A seed round issues 2,500,000 new shares to investors. Nobody sold a single share, but the company now has 12,500,000 shares outstanding, and your 45 percent became 36 percent.
Note what did not happen: your shares did not lose value per share. If the round priced the company at $5 per share, your 4.5 million shares went from an abstract number to a $22.5 million position on paper. Dilution is about fractions; valuation is about dollars.
Where dilution hides
The obvious source is the round itself. The less obvious ones bite harder: option-pool top-ups negotiated by investors before the round, warrants attached to venture debt, advisory shares, and the ESOP increases that accompany each hiring plan.
A common structure investors ask for is a 'pre-money option pool increase' — meaning the pool is topped up before the new money comes in, so existing holders absorb the dilution rather than the incoming investors. It is not sinister, but it must be negotiated, not accepted by default.
- Price the round including the option pool
- Count venture-debt warrants in your model
- Model advisory shares explicitly
- Recalculate after every single issuance
How much dilution is normal
A typical seed round sells 15 to 20 percent of the company. Series A sells another 20, and B and C take 15 each. Add option pools and a founder who never sells secondary can hold 30 to 40 percent at exit after four rounds — less with more rounds, more with a capital-efficient path.
The number founders regret is not the total given to investors; it is the total given away carelessly — pools sized for hiring plans that changed, advisory vesting that outlived the advisors, and bridges that converted on terms nobody modelled.
Frequently asked questions
Can I raise money without diluting?
Debt avoids share dilution — venture debt, revenue-based financing or a bank line. But debt has its own cost: warrants usually come attached, and repayment is a fixed obligation that equity never imposes.
What are anti-dilution provisions?
Clauses that protect investors in a down round by adjusting their conversion price. 'Broad-based weighted average' is standard and reasonable; 'full ratchet' punishes founders and should be negotiated away.
How do I model all of this?
With a cap table and a round-by-round spreadsheet. Our guide walks through building one in an afternoon.
Sources
Connectica provides information only, not financial, investment, legal or tax advice. Figures on this page are estimates and generalizations — confirm anything that matters with the relevant professional or authority.