Co-founder equity splits
Equal splits (50/50 for two founders, 33/33/33 for three) are the most common and often the most defensible — they signal equal commitment and avoid implicit power dynamics. Unequal splits are justified when one founder brought the IP, has significantly more domain experience, or is contributing meaningfully more time. Whatever the split, all co-founders should vest over 4 years with a 1-year cliff — including the CEO.
Vesting schedules: the only protection against a co-founder leaving
Standard vesting: 4 years, 1-year cliff, monthly vesting thereafter. The cliff means a co-founder who leaves in month 11 gets nothing. Monthly vesting after the cliff means each additional month earns 1/48th of total shares. Acceleration clauses (single-trigger, double-trigger) determine what happens at acquisition — double-trigger acceleration (change of control + termination) is standard and acquirer-friendly.
Option pool sizing by stage
Pre-Seed: 10% option pool is typically sufficient. Post-Seed: 15% is the standard ask from institutional seed investors. Series A: Investors typically require expansion to 15–20% post-money to cover 18–24 months of hiring. Series B: Pool is refreshed as needed; by this stage, total employee equity outstanding is often 15–25% of the cap table.
The pool is always created pre-investment (the option pool shuffle) — which means it dilutes founders, not investors. Negotiate the pool size based on your actual hiring plan, not the investor's standard ask.
Advisor equity: the benchmarks
Advisors typically receive 0.1–0.5% of the company, vesting over 2 years with no cliff. The exact amount depends on the advisor's contribution — a strategic advisor who opens three Series A conversations is worth more than a name on a website. Use FAST (Founder Advisor Standard Template) agreements for clean, standard documentation. More than 5% total advisor equity is a red flag for institutional investors.