Activist hedge fund Starboard Value has amassed a 4 percent stake in Zayo and is asking the U.S. communications infrastructure provider to consider a sale, according to a letter sent by Starboard to Zayo on Thursday.
Starboard's letter comes after Zayo on Wednesday canceled its March 14 analyst day and said it was evaluating all its options, sending its shares up 13 percent.
Zayo has lost a quarter of its market value in the last 12 months amid anemic revenue growth and heavy capital expenditure.
Starboard, which has been in contact with Zayo over the past several months, believes a sale of the company may be the best option for shareholders, and said the process must be conducted in a "purely objective way," according to the letter, a copy of which has been reviewed by Reuters.
Any potential conflict of interest, including the roles of members of management and the board in a potential deal, should not be allowed to affect the deliberations, Starboard wrote.
Zayo, which has a market capitalization of $6.5 billion and whose debt at the end of December totaled $5.9 billion, did not immediately respond to a request for comment.