After over two years of declining organic growth for U.S. tower companies, we are finally coming out of the trough in new leasing activity. New Street Research see an onslaught of amendment activity on the horizon as U.S. carriers rapidly deploy four new spectrum bands, beginning in earnest in the latter part of 2017. We maintain a detailed, carrier-by-carrier network deployment model, in which we estimate the cadence of colocation and amendment activity for the U.S. carriers, and use these estimates to drive U.S. tower revenue growth. Our model suggests that U.S. gross organic growth should increase by 150-200bps in 2018 and 2019.