The report - commissioned by MasterCard, one of the sponsors of the Champions League, ahead of Friday's knockout-stage draw - also found clubs reaching the knockout phase of the competition had earned an average of 50 million euros each.
This estimate included an average of 14 million euros from prize money and 10 million from ticket sales.
"The Champions League is probably the world's most valuable annual soccer club competition," professor Simon Chadwick of Coventry University in England, who conducted the study, told Reuters.
One third of the total six-billion-euro estimate was generated by increased UEFA prize money, with the rest mainly driven by television rights sales, sponsorship, advertising, ticket sales, gambling and travelling fans, Chadwick explained.
Clubs in Britain, Italy and Spain benefited from the biggest economic impact, pocketing a total of more than 330 million euros in prize money since December last year.
"The economic outlook is better this year than it was last year," Chadwick said.
"I think this is a direct reflection of additional revenues UEFA generated from TV rights, sponsorship deals and commercial partners."
The study also found that French club Girondins Bordeaux were the biggest earners, with 11.5 million euros in prize money alone from participating in this season's group phase, and a further three million euros from reaching the knockout stage.
The clubs that competed in the group stage and did not qualify for the Champions League knockout phase are estimated to have pocketed an average of 32 million euros each from their participation, the study said.
UEFA awards 3.8 million euros to each team that qualifies for the Champions League, plus 3.3 million euros for participating in the group stage. Reaching the first knockout stage brings an instant three-million-euro prize.
