(AP) — After a six-month review, Formula One announced Wednesday that it had rejected a bid by Andretti Global and General Motors to expand the grid for the 2025 season and said it believed the team would have been incapable of being competitive in the international racing series.

The decision outraged American fans of the series and left Michael Andretti and GM exploring potential legal avenues. F1 said it would be willing to revisit the issue if GM has an engine ready for the 2028 season, but was adamant and sharply critical in telling Andretti no for 2025 and 2026.

In reaching its decision, F1 said it did not believe Andretti would be a competitive team; that the Andretti name does not bring the value to the series that Michael Andretti believes it would; and that getting on the grid in the next two years would be a challenge Andretti has never faced before.

“The fact that the applicant proposes to do so gives us reason to question their understanding of the scope of the challenge involved,” F1 said in a statement. “Formula 1, as the pinnacle of world motorsport, represents a unique technical challenge to constructors of a nature that the applicant has not faced in any other formula or discipline in which it has previously competed. On this basis, we do not believe that the applicant would be a competitive participant.”

The Andrettis had realized in recent months that winning F1 approval was going to prove difficult but the dismissive announcement had an unmistakable sting. Mario Andretti is the 1978 F1 world champion, and son Michael ran 13 races in the 1993 season.

“I’m devastated,” the elder Andretti wrote on social media. “I won’t say anything else because I can’t find any other words besides devastated.”

General Motors under its Cadillac brand had signed on to partner with Andretti, but the bid received extreme pushback from most of the existing 10 teams, F1 leadership and Liberty Media Corp., the American company that owns the commercial rights to the series.

The process became more complicated when GM said in November it had registered with F1’s governing body to become an engine supplier starting in 2028. That backed F1 into a corner because it would be very difficult to turn away one of the largest automakers in the world, particularly an American company at a time the series has gained traction in the United States.

The United States hosted three races last season, more than any other country, and multiple U.S.-based companies from American Express and Visa to Oracle, Meta and MoneyGram have signed on as team sponsors over the last three seasons.

Andretti Cadillac said it “strongly disagrees” with the F1’s review of the application but gave no indication if it will pursue an antitrust lawsuit against Formula One Management or Liberty.

“Andretti and Cadillac are two successful global motorsports organizations committed to placing a genuine American works team in F1, competing alongside the world’s best,” the companies said. “We are proud of the significant progress we have already made on developing a highly competitive car and power unit with an experienced team behind it, and our work continues at pace.”

The Andrettis have championed their push to join F1 as creating a true American team that likely would feature California-raised IndyCar driver Colton Herta.

“While the Andretti name carries some recognition for F1 fans, our research indicates that F1 would bring value to the Andretti brand rather than the other way around,” F1 said in its decision.

F1 has only one American-owned team — Haas F1, which does not field cars for any American drivers — and Logan Sargeant of Williams Racing is the only American racing in the series.

Sargeant scored just one point in his rookie 2023 season and his renewal for a second season wasn’t completed until December. Haas, meanwhile, has never landed on a podium and consistently ranks at the bottom of the grid. Haas also just fired team principal Guenther Steiner, one of the stars of the Netflix docudrama about F1 that sparked fresh American interest in the series.

Governing body FIA in July had approved Andretti’s application to expand the grid by two cars, but F1 took six months to do its own review before Wednesday’s announcement — the deadline day that FIA had set.

F1 is interested in allowing Andretti in only when General Motors has an engine built for competition. Had Andretti received approval for 2025, he would have had to use another manufacturer’s engine until 2028.

F1 said it did not consult with the existing 10 teams in reaching its decision. But, the series said, expansion would be a stressor.

“The addition of an 11th team would place an operational burden on race promoters, would subject some of them to significant costs and would reduce the technical, operational and commercial spaces of the other competitors,” F1 said.

GM already has started development and testing of prototype technology, and it said building an F1 engine will help the automaker advance in areas including electrification, hybrid technology, sustainable fuels, high efficiency internal combustion engines, advanced controls and software systems.

F1 indicated it wants GM to succeed, a process the series believes will take years.

“Major automotive manufacturers have struggled in the past … (it) can take a manufacturer a number of years of significant investment in order to become competitive,” F1 said. “GM has the resource and credibility to be more than capable of attempting this challenge, but success is not assured.”

F1 has set new engine regulations for 2026 that place an emphasis on sustainable fuels and greater electric power. Six manufacturers have signed with the FIA to supply engines in 2026, including newcomer Audi, which will partner with Sauber. Ford plans to return to F1 in partnership with three-time reigning champion Red Bull. Honda also plans to return as an official supplier in 2026.

When the FIA initially opened the process for teams to express interest in joining F1, Andretti was the only applicant of seven to meet all the criteria for the FIA to expand the grid. With a car already built, the team had hoped to be competing in 2025.

Those hopes were dashed with F1’s decision even though F1 left the door open for 2028.

“We would look differently on an application for the entry of a team into the 2028 championship with a GM power unit, either as a GM works team or as a GM customer team designing all allowable components in-house,” F1 said. “In this case there would be additional factors to consider in respect of the value that the applicant would bring to the championship, in particular in respect of bringing a prestigious new OEM (original equipment manufacturer) to the sport as a PU supplier.”