Under Armour just took another step onto its rivals' turf.
The sports apparel maker has reached a 15-year, $280-million footwear and apparel deal with the University of California, Los Angeles, a source told CNBC on Tuesday. It trumps the previous largest agreement in college sports, Nike's $252-million deal with Ohio State University.
The agreement will be announced officially on Tuesday afternoon.
Under Armour previously signed contracts with the Notre Dame, Auburn and Wisconsin as it looks to grow its college sports presence. UCLA's deal with Adidas is set to expire next year.
Under Armour shares traded about 2 percent higher after the news.
— CNBC's Jessica Golden contributed to this report.