BOULDER, Colo.--(BUSINESS WIRE)--Zayo Group Holdings, Inc. (NYSE: ZAYO), a global provider of bandwidth infrastructure, today announced that it has entered into an agreement with certain of its stockholders to amend and extend the transfer restrictions under the Stockholders Agreement dated as of October 22, 2014. Holders of approximately 177 million shares of Zayo common stock are subject to the Stockholders Agreement, as amended. “The Company and its pre-IPO equity sponsors are committed to a