They looked at a sample of CEOs at some of the most valuable publicly traded companies in the U.S. to demonstrate the so-called birth date effect: nearly a quarter were born in the spring - 12.53% in March and 10.67% in April.
But just 12% of 375 CEOs at Standard & Poor's 500 companies were born in summer.
The study says the reason summer babies "underperform" when it comes to climbing the corporate ladder is the way American schools group children by age, which made the June and July study subjects the youngest in their respective classes.
The early success of older children in a grade tends to lead to greater opportunity and gives them an advantage, the researchers concluded.
The findings echo a similar theory proposed by Canadian writer Malcolm Gladwell, who wrote in his book Outliers about the age effect in pro hockey (though with slightly different results).
The UBC study shows that the way schools group students has an impact on their future success, the researchers said.
"We could be excluding some of the business world's best talent simply by enrolling them in school too early," study co-author Prof. Maurcie Levi said.