Rapoport noted the deal was with Nike, and Beckham's agent, Zeke Sandhu, worked out the five-year contract with the company.
According to Nick DePaula of Nice Kicks, Nike's 10-day window to match adidas' offer to the Giants star ended Tuesday. Nike matched it and kept Beckham aboard with a five-year deal thought to be worth more than $29 million, per DePaula.
Art Stapleton of The Record reported incentives could push the deal to eight years, $48 million.
DePaula cited multiple brand sources who said Beckham didn't require a signature cleat in negotiations but stressed he wanted to be a "brand icon" for Nike.
Beckham has played like an icon through the first three seasons of his NFL career. He's surpassed 1,300 receiving yards, reached double-digit touchdown receptions and made the Pro Bowl all three years.
Given Tuesday's news, he will likely continue to put up head-turning numbers with the Nike swoosh on his cleats.