How about http://www.psychologicalscience.org/index.php/news/releases/are-the-wealthiest-countries-the-smartest-countries.html ?

They found that intelligence made a difference in gross domestic product. For each one-point increase in a country’s average IQ, the per capita GDP was $229 higher. It made an even bigger difference if the smartest 5 percent of the population got smarter; for every additional IQ point in that group, a country’s per capita GDP was $468 higher.

Citing "Cognitive Capitalism: The impact of ability, mediated through science and economic freedom, on wealth". (PDF not immediately available in Google.)

EDIT: efm found the PDF: http://www.tu-chemnitz.de/hsw/psychologie/professuren/entwpsy/team/rindermann/publikationen/11PsychScience.pdf

Or http://www.nickbostrom.com/papers/converging.pdf :

Economic models of the loss caused by small intelligence decrements due to lead in drinking water predict significant effects of even a few points decrease (Salkever 1995; Muir and Zegarac 2001). Because the models are roughly linear for small changes, they can be inverted to estimate societal effects of improved cognition. The Salkever model estimates the increase in income due to one more IQ point to be 2.1% for men and 3.6% for women. (Herrnstein and Murray 1994) estimate that a 3% increase in overall IQ would reduce the poverty rate by 25%, males in jail by 25%, high-school dropouts by 28%, parentless children by 20%, welfare recipients by 18%, and out-of-wedlock births by 25%.

EDITEDIT: high IQ predicts superior stock market investing even after the obvious controls. High IQ types are also more likely to trust the stock market enough to participate more in it