[iaw]

Not dumb, this stuff isn't really taught unless you explicitly pursue it.

One note: the return on some companies may be higher and others lower, the issue is that the risk for money in companies is higher.

Very simplistic example: the US government can offer you a flat 5%, a company investment offers 10% half the time, 0% the other half.

One is a sure thing, one is a gamble. The more the 'gamble' the more risk and that is a driving factor in investments. People are willing to take huge risks if the payoff is very large (Look at Michael Burry and the big short)