Fully diluted ownership is your economic share of the company measured against the broadest reasonable share count—not just the stock certificates issued today.

How it works

Take the shares you hold (common or preferred on an as-converted basis) and divide by the fully diluted total from the cap table. Employee option grants count even if unvested or unexercised; SAFEs and notes count using their conversion mechanics at the relevant valuation. After a Series A, a founder might show 35% fully diluted versus 45% on issued common alone because of the new investor, refreshed option pool, and advisor grants. Ownership shifts with every financing, pool increase, and secondary unless you participate pro-rata.

Why it matters

• Founders: Model dilution across planned rounds so you know where you land if you raise twice more without mega-up rounds.
• Investors: Track fully diluted ownership for fund reporting, reserve planning for follow-ons, and governance thresholds tied to percentage blocks.

Common mistake

Celebrating a term sheet percentage without confirming whether it is pre- or post-option-pool expansion and whether SAFEs are included in the denominator.

Related ideas

Pro-rata rights, fully diluted cap tables, liquidation preference stacks, and founder secondary sales.