Startup founders, co-founders, and early-stage entrepreneurs planning to raise investment or grant employee equity.
Readers will gain insights on dilution mechanics, when it's value-creating, normal benchmarks, protection strategies, and tools like cap tables to make smarter equity decisions.
Key Takeaways
- Dilution reduces ownership percentage when new shares are issued, but can be beneficial if company value grows more than the dilution.
- Typical dilution: 10-20% in seed, 20-25% Series A; founders end with 10-30% at exit, but 15% of €50M > 100% of nothing.
- Ownership dilution ≠ economic dilution; focus on absolute value increase.
- Option pools dilute founders first; create pre-investment. Track liquidation preferences and convertibles for true impact.
- Strategic dilution accelerates value: raise needed capital at fair valuations, model cap tables, ask if worth it.

Dilution Explained: What Happens When You Issue New Shares?
What Is Dilution?
Dilution happens when your company issues new shares and your ownership percentage decreases. You still own the same number of shares, but they represent a smaller slice of the company. Think of it like a pizza - you own half, someone adds more pizza, your slices are now less than half.
A Simple Example
You own 50 shares out of 100 total. That's 50% ownership. The company issues 100 new shares to an investor. Now there are 200 total shares. You still own 50 shares, but that's only 25% now. Your ownership percentage was cut in half.
Is Dilution Always Bad?
No, dilution can be good if it increases your company's value. Owning 25% of a €2 million company beats owning 50% of a €500,000 company. Dilution becomes bad when your slice is worth less than before. This happens when shares are issued too cheaply or without adding value.
Why Companies Issue New Shares
Companies issue shares for several reasons. Raising investment brings in cash to grow the business. Employee equity helps attract and retain talent. Most dilution in startups comes from fundraising and employee options.
How Much Dilution Is Normal?
Seed rounds typically dilute founders by 10-20%. Series A takes another 20-25%. Employee option pools usually account for 10-20% before each round. By exit, founders often own 10-30% of the company they started. But 15% of €50 million beats 100% of nothing.
Ownership Dilution vs Economic Dilution
Ownership dilution means your percentage decreases. Economic dilution means the value of your shares decreases. You can have ownership dilution without economic dilution if company value increases. Example: You own 50% of a €1 million company (worth €500,000). After investment, you own 40% of a €3 million company (worth €1.2 million). Your percentage went down, but your stake's value more than doubled.
When Dilution Hurts
Down rounds raise money at lower valuations than before. Excessive employee grants give away too much equity early. Bad investment terms heavily favor investors over founders. These leave founders with tiny stakes in companies that never grow enough.
Protecting Yourself From Dilution
Pre-emption rights let you buy new shares to maintain your percentage. Anti-dilution provisions protect investors if you raise at lower valuations later. Vesting schedules ensure people earn equity over time. Creating option pools before investment means investors share the dilution.
Option Pool Dilution
Option pools create significant dilution for founders. Investors require 10-20% pools before they invest. This dilution comes from founders, not investors. Example: Founders start at 100%. Create 15% option pool (founders now at 85%). Investor takes 20% (calculated after pool exists). Founders end up with 68%, investor gets 20%, pool is 12%. This math prevents surprises during negotiations.
Calculating Post-Dilution Ownership
The formula is simple: Your shares ÷ Total shares after issuance × 100. You own 60,000 shares out of 100,000 total (60%). Company issues 50,000 new shares. Your new percentage is 60,000 ÷ 150,000 = 40%. Always ask "how many total shares after this?" when evaluating deals.
Dilution and Valuation
Pre-money valuation is company value before investment. Post-money valuation is value after investment. Example: €2 million pre-money, investor adds €500,000. Post-money is €2.5 million. Investor owns 20% (€500,000 ÷ €2.5 million). Existing shareholders diluted from 100% to 80%.
Liquidation Preferences Create Hidden Dilution
Investors often get paid first in an exit. Example: Investor puts in €1 million for 20% with 1× liquidation preference. Company sells for €3 million. Investor gets €1 million back first, plus 20% of remaining €2 million. Investor receives €1.4 million total (effectively 47%, not 20%). Your economic stake is more diluted than ownership percentage suggests. Always understand investor preferences, not just percentages.
Convertible Notes and SAFEs
Convertible instruments create delayed dilution. You won't know exact dilution until they convert. Example: €100,000 SAFE with €2 million cap. Next round values company at €4 million. SAFE converts at €2 million (50% discount). SAFE investor gets twice as many shares as current investors. Track all convertibles to understand total potential dilution.
Managing Dilution Over Time
Only raise what you need when you need it. Negotiate higher valuations to reduce dilution. Be generous but not excessive with employee equity. Understand all terms - preferences matter as much as percentages. Model future rounds using a cap table. Most dilution complaints come from avoidable early mistakes.
The Key Question
Don't ask "am I being diluted?" Ask "is this dilution worth it?" If you need €500,000 to build your product, giving 20% makes sense. If you're giving 40% because you're nervous, reconsider. Make dilution decisions based on whether they accelerate building value.
What Good Dilution Looks Like
You raise money at a fair valuation. The capital helps you hit important milestones. Hitting milestones increases company value more than the dilution cost. Your smaller percentage of a bigger company is worth more. Everyone's absolute returns increase despite decreased percentages. That's strategic dilution creating value for everyone.

Stuart Connolly is a corporate barrister in Ireland and the UK since 2012.
He spent over a decade at Ireland's top law firms including Arthur Cox & William Fry.







