There are at least 400 of the S&P 500 companies that I don’t meaningfully understand what they do, how exactly they make money, what their defensible moats are,

There are at least 400 of the S&P 500 companies that I don’t meaningfully understand what they do, how exactly they make money, what their defensible moats are, etc. I still invest in S&P 500 ETFs and believe that to be prudent.