In a letter to Verizon general counsel John Scott, Kaplan asks about the timetable Verizon has set for building out networks on the spectrum. Winners of the 2008 auctions were required to build out a network by 2013 or face a reduction in the term of their license.
Kaplan also asks about the "relevance" of plans to sell its licenses to the SpectrumCo deal, and if Verizon would abandon plans to sell the spectrum if the SpectrumCo deal isn't approved.
Verizon must submit responses to Kaplan's questions by May 22, he said.
A Verizon spokesman said the company had no comment on today's letter.