Research from the University of Cambridge suggests that movements of money in the financial markets are correlated to stock traders’ levels of two hormones: the steroids testosterone and cortisol.

They found that when the traders made more money, they had elevated levels of testosterone. When the markets were particularly variable, they had elevated levels of cortisol. They also found that traders who started their days with elevated testosterone made more money than those who didn’t, but that too much testosterone leads to too much aggression and reckless decision making.