Telecommunications company Crown Castle Inc. has reached an agreement with an EQT AB fund and Zayo Group Holdings Inc. for each to buy separate parts of its fiber business for a combined value of $8.5 billion.

Crown Castle shares rose after it said it was selling part of its business to focus on its core towers segment. The stock increased more than 10% Friday, regaining all but about 3% of its losses over

Crown Castle sold its fiber optics business to EQT Active Core Infrastructure fund and Zayo Group Holdings for a total of $8.5 billion.