Fitting its aggressive personality, Select Technology battered investors in the tech crash at the turn of the century and roughed them up again in the 2008 crash.

FORBES: The Forbes Mutual Fund Honor Roll

Frey and Benz are exemplary in testing for the possibility that happier people are more likely to be self-employed, or that the sort of personality most likely to enjoy self-employment select into self-employment.

FORBES: Happiness, Freedom, and Autonomy