The electronics retailer had helped Target operate Target Mobile in 1,500 of the latter company's stores. Target Mobile lets customers purchase mobile phones and activate contracts with the nation's top carriers.
According to RadioShack, the deal "provided RadioShack access to manage Target's post-paid mobility business, but RadioShack did not manage the prepaid mobility business or the wider range of accessories offered in Target stores."
RadioShack said the companies had been renegotiating terms since October 2012 to "establish an agreement that would be profitable to both companies." The negotiations failed.
Separately, Target announced it had reached agreements with two privately held companies, Brightstar and MarketSource, to assist it in the sale of Target Mobile services.