Pac-12, the US college sports conference, is on the brink of collapse in the wake of decisions by the University of Oregon and the University of Washington to play for fellow conference Big Ten in 2024.

The Big Ten Conference will now have 18 teams going into the 2024-23 academic year – the largest in college football history – while Pac-12 has been reduced to only four members.

The defections have been driven by American football and the money that it generates. The Big Ten has a seven-year, $7-billion media rights deal with multiple networks, while fellow league the Big 12 agreed to a $2 billion with national network Fox and international sports broadcaster ESPN last year.

Big Ten commissioner Tony Petitti said: “We are excited to welcome the University of Oregon and the University of Washington to the Big Ten Conference.

“We look forward to building long-lasting relationships with the universities, administrators and staff, student-athletes, coaches, and fans. Both institutions feature a combination of academic and athletic excellence that will prove a great fit for our future.”

Oregon and Washington are the third and fourth Pac-12 teams to join the Big Ten for 2024, following the University of Southern California (USC) and the University of California-Los Angeles (UCLA) announcing their departure. The University of Colorado followed soon after by stating it would join the Big 12 next year.

With the departures of Arizona, Arizona State, and Utah to the Big 12 Conference, the Pac-12, which has existed since 1915, now has just four teams left in the University of California, Berkeley, Oregon State University, Stanford University, and Washington State University.

The future of Pac-12 is unclear but the four teams left in Pac-12 are understood to be looking to join other conferences including the Mountain West Conference and Atlantic Coast Conference, which would end Pac-12 entirely.

In a statement, Pac-12 said: “Today’s news is incredibly disappointing for student-athletes, fans, alumni, and staff of the Pac-12 who cherish the over 100-year history, tradition, and rivalries of the Conference of Champions.

“We remain focused on securing the best possible future for each of our member universities.”

The news came a week after it was reported Pac-12 was mulling a potential media rights deal with tech giant Apple. The Pac-12 has been negotiating its next set of media rights deals since last July when it was authorized to begin discussions earlier than planned.

However, the league’s best offer was $20 million annually per school (before incentives), while Big 12 teams are set to earn $31.7 million annually. It was also reported the deal did not satisfy distribution expectations with the Apple deal taking a primarily subscription-based approach.

Oregon and Washington, meanwhile, are due to receive a $35 million to $40 million share per year when they join Big Ten.

The 2023 NCAA Division regular season is due to begin on August 26 and end on December 9.