We are all, to a certain extent, portfolio managers.
Whether you do it yourself or someone else handles it on your behalf, your portfolio of public equities is the result of thousands of decisions over a lifetime. Your returns are shaped by your time horizon, asset allocation, style, geography, size, sector, company selection and more.
But the single greatest factor that will determine your portfolio's returns is no other than your temperament.
Success in investing doesn’t correlate with IQ. Once you have ordinary intelligence, what you need is the temperament to control the urges