Dilution

TL;DR

The reduction in an existing shareholder's ownership percentage caused by issuing new shares in a financing or an option grant.

Dilution is the inevitable consequence of issuing new equity. Every priced round dilutes existing shareholders proportionally to the new shares created. A $10M raise at a $40M post-money dilutes existing shareholders by 25%. Option pool top-ups, anti-dilution adjustments, and SAFE conversions all add to cumulative dilution.

Founders should model cumulative dilution from pre-seed through Series C to understand realistic ownership at exit. Typical founder ownership at IPO ranges from 10–25%, depending on capital raised and round structure.

Formula

Dilution = New Shares ÷ (Existing Shares + New Shares)

• New Shares — Shares issued in the new round
• Existing Shares — Shares outstanding before the round (fully diluted)

Worked example

Founders own 100% of 8M shares pre-investment. Round issues 2M new preferred shares at $5 each ($10M raise, $50M post-money). Founder ownership drops from 100% to 8M ÷ 10M = 80% — that's 20% dilution.

Common pitfalls

• Optimizing each round in isolation instead of modeling cumulative dilution to exit.
• Underestimating dilution from convertible instruments.
• Ignoring how anti-dilution provisions interact with future down rounds.

When this shows up in a pitch deck

Dilution math drives the cap-table model in the data room; deck content rarely names it directly.

See Dilution in context

Dilution shows up most often in these scoring rubrics and investor profiles — jump straight to who cares about it and how to pitch them.

For investor types

• Private Equity — Profitability & Scale

Related terms

• Pre-Money Valuation — The agreed-upon value of the company immediately before a new investment round closes — pre-money + new money = post-money.
• Option Pool — Equity reserved for future employee, advisor, and contractor grants, usually sized as 10–20% of fully diluted shares.
• Anti-Dilution (Weighted Average) — A standard anti-dilution provision that adjusts a prior preferred holder's conversion price using a formula weighted by the size of the down round.
• Down Round — A funding round priced at a lower valuation per share than the previous round, typically triggering anti-dilution adjustments and signaling stress.
• Fully Diluted Shares — The total share count assuming every option, warrant, convertible note, SAFE, and reserved pool has been exercised or converted.

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