An arbitration panel has denied a request from Sprint Nextel Corp. affiliate Nextel Partners Inc. that sought to ban the newly merged parent company from rolling out a new unified Sprint cellular brand, the companies said Tuesday.

Sprint Nextel began marketing its new brand nationally last week. The company, formed less than a month ago by the $35 billion merger of Sprint Corp. and Nextel Communications Inc., is using the Nextel name only as a product brand.

Sprint Nextel owns about one-third of Nextel Partners, which sells Nextel services in more than 30 states. Nextel Partners has asked its shareholders to exercise a contract provision that would require the parent company to buy the smaller telecom, but the two sides have disagreed over the value of the affiliate’s shares.