Shares of the U.S.-based telecom tower companies fell as much as 4 percent on Friday after Reuters exclusively reported that T-Mobile US Inc and Sprint Corp could announce a deal as early as next week. Shares of Crown Castle International Corp and SBA Communications Corp fell about 4 percent, while American Tower Corp fell 1.3 percent in afternoon trade.

Tower companies earn money by leasing out space for cellular antennas and when two telecom companies merge they look at cancelling contracts for overlapping towers to save costs, which could eat into revenue.