Continental Tire will exit IMSA competition at the end of 2018, including title sponsorship of the Continental Tire SportsCar Challenge, with IMSA electing not to extend its long-standing partnership, the tire manufacturer announced on Wednesday.

The change comes after a nearly decade-long relationship with IMSA, which has included the exclusive tire contract for the Prototype, Prototype Challenge and GT Daytona classes of the WeatherTech SportsCar Championship since its launch in 2014.

Continental joined the sports car series in 2010, in Grand-Am, and has provided significant investment within the sport through various marketing activities.

Its five-year contract, signed pre-merger, expires at the end of 2018 and IMSA to evaluate proposals from multiple tire manufacturers to take over the exclusivity contract.

Continental says its proposal for a multi-year extension included a “significant increase” in investment.

“We are extremely proud of the contributions we’ve made to sports car racing in the U.S.,” said Travis Roffler, director of marketing of Continental Tire the Americas.

“We worked diligently to continue our support of IMSA, and the growth of the sport, and are disappointed in IMSA‘s decision to go a different direction. We remain committed to making the 2018 IMSA season a fantastic year for the fans, drivers, and all the teams.

“The relationships we’ve built over the years are many, and we thank everyone for their continued support of the Continental Tire brand. We also want to thank the fans. Without you, there would be no racing.“

It’s understood Michelin, along with Goodyear and Pirelli have all entered discussions with IMSA for the 2019 contract.

The French tire giant, which already supplies teams in the GT Le Mans class, is believed to be the leading candidate, which would include title sponsorship of IMSA’s SportsCar Challenge as well as being the exclusive tire provider for the entire WeatherTech Championship.

When reached by Sportscar365, a Michelin spokesperson has deferred all comments to IMSA, which has yet to issue a statement on its tire contract situation for 2019 and beyond.