Antonio Conte's side were knocked out of the competition in December after finishing third in Group B.
Juve's Champions League fate eventually went down to the final group game and a 1-0 defeat at Galatasaray saw the Turkish champions progress at the expense of Conte's men, a result that Marotta admitted has had a significant financial impact on the Turin outfit.
"A football club has to deal with an imponderable factor," he told Corriere dello Sport.
"And that's results on the field. The imponderable is the uncertainty of the game.
"Just one goal can have such a huge meaning. Our exit from the Champions League cost us €25m."
But Marotta is upbeat about Juve's overall financial performance, which he says has been positively impacted by the 2011 move to the 41,000-seater Juventus Stadium.
"Our financial growth compared to the rest of Europe is slow - compared to England for instance," Marotta added.
"In some stadiums we have under 50 per cent attendance. But for us, the new stadium has played a key role in the diversification of our revenues.
"More people through the turnstiles means more opportunities in the market."
