Why fully diluted shares matter to a first-time founder
Ownership percentages and per-share values can look overstated when calculated only from shares currently issued. Including potential shares shows the dilution already embedded in options and convertible instruments. Investors may define the denominator differently, especially around an option-pool increase, so founders must read the term sheet formula.
Examples of fully diluted shares
A company has 800,000 ordinary shares, options for 100,000 shares and a note expected to convert into 100,000 shares. Its simplified fully diluted count is 1,000,000. A founder holding 400,000 shares therefore owns 40% on that basis, not 50% based only on issued ordinary shares.
Common misunderstanding
They are not all necessarily issued, outstanding or able to vote today. The number is a scenario-based denominator that assumes specified rights convert or are exercised. It may exclude unallocated option-pool capacity or instruments whose conversion depends on price, so two documents can report different valid totals.
When to use it
Use the count when modelling fundraising, option grants, exits and ownership percentages. Reconcile every option, warrant and convertible instrument and state the assumptions beside the number. Ask legal and finance advisers to confirm the contractual definition before agreeing a valuation expressed on a fully diluted basis.