Coaches and former players are another popular alternative. The former University of Connecticut coach Jim Calhoun and the former Duke star J. J. Redick lent their names to a campaign from Unilever's Dove Men+Care, while Pizza Hut enlisted another former Duke star, Grant Hill, to help tout a limited run of shoes called Pie Tops, essentially high-top sneakers that have the ability to order pizza.
"It felt very authentic to have an actual former player wear them and use them, and that's where we landed on with Grant Hill," said David Daniels, vice president of media and advertising at Pizza Hut. "The beauty of the N.C.A.A. is that it's a feeder for professional sports, and there are iconic athletes that have come out that are household names or just relatable and authentic on camera that help tell your brand story."
Of course, these workarounds bring to the surface some of the concerns critics have expressed about the increased commercialization of college sports, especially football and men's basketball, and the extent to which the billions of dollars in revenue fail to trickle down to the players. If everyone is making millions off the tournament, they say, why can't the players get a slice of the pie? (In fact, college athletes are penalized if they attempt to capitalize on their athletic endeavors in any material way.)
The N.C.A.A.'s corporate partnerships are managed for the tournament by CBS Sports and Turner, which hold the basketball tournament's broadcast and multimedia rights through 2032. The number of official sponsors has increased from about a dozen in 2011, according to Octagon. The tournament brought in a record $1.24 billion in national television ads last year, an increase of nearly 5 percent from 2015, with much of that coming from official partners, according to estimates from Kantar Media.
The N.C.A.A. said its sponsors, three of which are designated "champions" while the rest are "partners," support athletes through opportunities like speaking at events, granting scholarship money to general funds and bringing fans to events to cheer for them.
The bylaws against paid endorsements are meant to protect college athletes, said Jeff Jarnecke, director of championships and alliances at the N.C.A.A. "The line we're trying to avoid, or at least not walk up to, is the perception of an endorsement by our student athletes of a particular product," Mr. Jarnecke said.
Brand endorsements take other forms. Some advertisers may aim to promote themselves through student sections at games, Mr. Wardle said, pointing to college football promotions in recent years from Taco Bell and Coke Zero.
Buffalo Wild Wings, which is the "official hangout for N.C.A.A. sports," sponsored 23 colleges this year, including the University of Miami and the University of Louisville. The chain and LG worked with a firm called Learfield in order to use the names, logos and mascots of various universities in their advertising.
Colleges' intellectual property rights are becoming "the biggest thing in our lineup," said Roy Seinfeld, executive vice president of national sales at Learfield, which manages multimedia rights for more than 125 colleges, universities and conferences. Brands are "really creative at using the power of the logo when they don't have the power of the personality," he said.
Social media stars are also getting in on marketing budgets. Pizza Hut, which made 64 pairs of its pizza-ordering shoes, sent some to "select influencers" in order to generate buzz. Wendy's, as part of a cross-country road trip to the Final Four in Phoenix, will work with internet personalities like Brodie Smith and King Bach.
Without being able to include the players in their marketing, however, brands can sometimes find themselves stretching to connect with their audiences — equating, say, fans' loyalty to their teams to a company's corporate culture.
Wendy's, for instance, said that it was able to become the tournament's official hamburger "because, like the fans who go to great lengths to support their teams, Wendy's goes to unreasonable efforts to make sure every hamburger it serves is made with fresh, never frozen beef."