These and many more allegations were revealed in a series of complaints made public by federal investigators in New York on Tuesday. The complaints depict a thriving black market for teenage athletes, one in which coaches, agents, financial advisers and shoe company employees trade on the trust of players and exploit their inability to be openly compensated because of N.C.A.A. amateurism rules.

College basketball has a long, baroque history of malfeasance involving under-the-table deals, but rarely, if ever, have federal investigators exposed such widespread corruption. The closest analogue is probably the point-shaving scandals of the early 1950s, said Rodney K. Smith, a law professor who has studied the history of the N.C.A.A.

“For these men, bribing coaches was a business investment,” Joon H. Kim, the acting United States attorney for the Southern District of New York, said while announcing federal bribery, fraud and other corruption charges. “They knew corrupt coaches, in return for bribes, would pressure the players to use their services. They also knew that if and when those young players turned pro, that would mean big bucks for them.”

This vision of what Kim called “the dark underbelly of college basketball” led to the arrests of nearly a dozen people, including four Division I assistant coaches and the global marketing director for Adidas basketball. Kim said the investigation was continuing, and the disclosures made on Tuesday seemed to promise further revelations of wrongdoing that could upend one of the country’s most popular sports, whose annual tournament provides the N.C.A.A. with the vast majority of its income.

Across three complaints, two broad schemes were alleged. One involved bribing four assistant coaches — at Arizona, Auburn, Oklahoma State and Southern California, all programs in the so-called Power 5 conferences of college sports — to persuade players to send business to certain financial advisers once they turned professional. The other involved efforts to secretly funnel money from Adidas to three players and their families in exchange for the players’ commitments to play at two Adidas-sponsored college programs and to later sign sponsorship deals with the company once they turned pro.