Successful financial traders may be born, not made. That’s the implication of a new study which found that traders who excel at short-term or “high-frequency” trading may have been exposed to higher levels of testosterone in the uterus.

These traders can hold their stock for minutes, or mere seconds, before selling – requiring high levels of confidence and fast reaction times.

Last year, John Coates at the University of Cambridge, UK, and his colleagues found that traders who started their days with elevated testosterone made more money than those who didn’t.

But successful traders aren’t all macho and aggressive risk-takers – characteristics typically associated with high testosterone. “The good ones are very calm, they don’t lose their temper, and probably the most extreme sport they do is fly fishing,” says Coates. “They’re not cavemen.”


Because individual responses to testosterone can be affected by how much of the hormone you were exposed to in the uterus, Coates wondered if this could also be exerting an effect. So he recruited 49 male traders from the City of London and looked at their index-to-ring-finger ratio – a marker of prenatal testosterone exposure.

Profitable digits

He found that traders with a longer ring fingers, and therefore higher prenatal testosterone, made on average six times the profits of traders exposed to low levels of the hormone, and tended to remain traders for longer.

Previous studies have also suggested a link between a low index-to-ring-finger ratio and autism, and better sporting ability.

“This study provides evidence for human beings of what we know from studies of animals, that exposure to sex hormones early in life predisposes the nervous systems and resulting behavior to develop in certain ways,” says Bruce mcEwen of the Rockefeller University in New York. “In this case the development of the risk taking, visual-motor skills, etc that make for success in this kind of rapid stock trading.”

“However, it takes environment, or the experiences and opportunities that a person has, to further shape the brain to this particular career path,” he adds.

And while finger length may provide some indication of your suitability to financial trading, Coates cautions bosses against using it to make hiring decisions.

Goodbye CV?

Other factors undoubtedly play a role, and the effects of high prenatal testosterone may be a disadvantage in other types of trading. For example, other studies have suggested that people with a high index-to-ring-finger ratio make better mathematicians, so they may excel in more analytical city jobs.

“My hunch is that this correlation could reverse in types of trading where people position for long-term [as opposed to short-term] gains,” says Coates.

However, John Manning, an evolutionary psychologist and author of The Finger Book (read our review) says it would be interesting to see if finger ratios correlate with other professions.

For example, you might expect a low index-to-ring-finger ratio to correlate with military ability, while a higher ratio might correlate with performance in personnel management, or in professions such as nursing, occupational therapy and the teaching of very young children, he says.

Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0810907106)