Spain?s Cellnex Telecom, S.A. (BME:CLNX) is exploring a sale of a stake in its Nordic operations that could value the unit at to EUR 1 billion ($1.11 billion), people familiar with the matter said, as the company looks to pay down debt. The telecoms group is working with bankers at AZ Capital, a Spanish boutique financial advisory firm, to gauge interest in its Swedish and Denmark operations, said the people, who spoke on condition of anonymity.