Nike, which has sponsored the iconic British team since 2002, walked away from the bargaining table after German rival Adidas reportedly agreed to more than double Nike's current contract.
"Manchester United is a great club with passionate fans," Nike said in a statement.
"Any partnership with a club or federation has to be mutually beneficial, and the terms that were on offer for a renewed contract did not represent good value for Nike’s shareholders. We look forward to a successful final season with the club."
British media said that Adidas is now close to signing a 10-year contract to equip the Red Devils with clothing and footgear for 750 million pounds ($1.3 billion).
Nike had reportedly been prepared to offer $600 million over 10 years. Its current contract, which expires after the 2014-15 season, was for $510 million over 13 years.
The fight for sponsorship, which reportedly also included Puma and Warrior Sport of the US, came despite a disappointing season for the storied club.
Manchester United finished in seventh place in the English Premier League and failed to qualify for European competition for the first time since 1990.
In late trade, Nike shares fell 1.2 percent to $77.70, while Manchester United declined 0.5 percent to $17.75.