I don't think putting all your net worth in S&P would be considered diversified.
With an MSCI world, those companies would drop to ~22% exposure. Throw a bit of real estate, more exposure to your home country if you are not in the US some real estate, some bonds and you can make it drop to <10%.
With an MSCI world, those companies would drop to ~22% exposure. Throw a bit of real estate, more exposure to your home country if you are not in the US some real estate, some bonds and you can make it drop to <10%.