The central justification T-Mobile and Sprint are offering for their merger is also why it’s likely to run into trouble with regulators. According to the companies’ merger website, “Only the New T-Mobile will have the right mix of available spectrum” to build a nationwide 5G network in the near-term. The merger’s aggregation of substantial spectrum assets and potential to result in a dominant 5G network controlled by a single firm presents competitive problems.

When a merger would result in one company controlling 194 MHz or more of available mobile spectrum in a single market, the Federal Communications Commission (FCC) analyzes that market in greater detail. When this 194 MHz “screen” would trigger a substantial number of markets nationwide, the FCC subjects the entire transaction to additional review.

It appears the companies’ spectrum holdings will subject the merger to strict regulatory scrutiny in many markets and perhaps on a national basis. Based on the spectrum analysis in the FCC’s most recent mobile competition report, New T-Mobile would have about two times as much spectrum (282-298 MHz) as AT&T (148 MHz) and two-and-a-half times more spectrum than Verizon (115 MHz) overall. The post-merger company would have about the same amount of low-band spectrum as Verizon and AT&T, but would have gobs more of the mid-band spectrum that Sprint considers especially well-suited to the deployment of 5G networks.