Renault has taken its share of the responsibility for Red Bull's poor form this season and hopes this year will be a one off.
Red Bull finished second in the constructors' championship in 2014 but dropped to fourth this year, laying much of the blame on Renault. Toro Rosso, which was also supplied by Renault this year, was targeting fifth in the championship but finished seventh.
"Fourth in the championship for Red Bull is no doubt hard to accept and we all share that responsibility," Renault's F1 managing director Cyril Abiteboul said. "At Toro Rosso, the championship position may not be as hoped, but with more than double the points of 2014, it's been a strong year overall for them and we are proud to have worked together to achieve this."
The French manufacturer has yet to confirm its plans for 2016, but Abiteboul hopes the disappointment of 2015 was just a one off.
"At the end of a very challenging season, both on and off track, I would like to thank everyone at Viry-Châtillon for their hard work. At the start of the year when we came under fire it would have been easy to lose motivation, but all have kept their heads down and kept development on track. We have not reached the targets we set for ourselves, but I hope this year will be seen as an aberration to our usual good form."