According to a report from Bloomberg, FCC chairman Tom Wheeler is planning on limiting the amount of spectrum any one company can purchase at the auction. The plan has been disseminated during non-public meetings. FCC commissioners will be voting on the plan next month.
The spectrum is being taken from television broadcasters and is being auctioned to mobile carriers to meet the skyrocketing demand for mobile spectrum. It will be the largest auction for the airwaves since 2008, when $19 billion in winning bids was accepted by the government. However, 80% of that money came from Verizon and AT&T, the nation's top two mobile carriers.
What makes this spectrum so valuable is the low band (600MHz) of the airwaves. This allows the signal to travel longer distances and more easily penetrate buildings.