American Tower on Tuesday gave its full year 2017 outlook a $100 million boost, in a change one analyst chalked up to one of the top two U.S. carriers.

In its 8K filing, American Tower revealed it signed an “amended master lease agreement with one of its tenants,” and consequently expects to realize “at least $100 million in additional straight-line revenue for the year.” The company now anticipates total property revenue of $6.31 billion to $6.49 billion, net income of $1.275 billion to $1.345 billion, and adjusted EBITDA of $3.910 billion to $4.01 billion for the full year 2017.

According to Wells Fargo Senior Analyst Jennifer Fritzsche, that mystery tenant is likely either AT&T or Verizon.

While some analysts, like those at New Street Research, pointed the finger at AT&T, Fritzsche said her suspicions leaned more toward Big Red. “If we were to speculate, our belief is this could be more related to VZ activity given it had a holistic MLA with AMT in the past,” Fritzsche observed.

That’s not to say AT&T’s tower game is lacking. Fritzsche noted AT&T is also expected to increase tower spending once it officially locks in the FirstNet build contract. And that announcement could come quite soon.

The U.S. Court of Appeals shot down a lawsuit from Rivada Mercury on Friday, putting AT&T firmly in the top slot to take home the bid. FirstNet CEO Mike Poth said he was “pleased” with the decision and noted FirstNet plans to move quickly to finalize the contract award.

More on why AT&T is the favorite for the bid can be found here.