How much of my money should ever sit in individual stocks?

There is no magic percentage, but the founder-specific point is that you are already making one giant concentrated bet: your company. Your equity, your salary, and often your reputation all ride on it. So the money outside the company is where you want diversification and calm, not a second high-risk portfolio. Many people who do pick stocks treat it as a small satellite, a slice they can afford to see cut in half without it touching their life, while the core stays in low-cost index funds. A useful test: if this stock went to zero, would it change your plans? If yes, it is too big. Keep individual stocks a minority of your investable money, and keep the emergency buffer and core untouched. Tax on any gains changes over time, so confirm current rules with a CA or a qualified advisor.