The government is planning to allow O2 and Vodafone to keep the sections of the radio spectrum they bought in 1980.
However, as part of the deal there will also be a cap on the purchase of further space for mobile broadband firms, according to the Guardian.
Companies will not be allowed to acquire any more of the spectrum after space is freed up following the complete switchover from analogue to digital TV unless they sell some of their 900MHz holdings.
The 900MHz spectrum is currently owned by O2 and Vodafone, but many of their competitors are hoping to own part of it.
The proposal is part of the Digital Britain plan, which is intended to grant broadband access to everyone in Britain.
This cap should help to push forward the development of Digital Britain, technology minister Lord Carter's plan for every home in the country to have access to a broadband connection of at least 2Mb.
Kip Meek, the communications minister's lieutenant, was responsible for putting the capping plan together.