Ultimately it's about risk (permanent loss) control, and if you've done the research into those couple of companies, have high confidence in their continued suc

Ultimately it's about risk (permanent loss) control, and if you've done the research into those couple of companies, have high confidence in their continued success, and are diligent in continuing to update your views, then it sounds like you're managing risk well. There's always the chance of unknown, idiosyncratic, and potentially disruptive factors though--from a financial planning and risk management perspective, even founders are urged to diversify away from their own company's equity eventually, regardless of how successful they are.