STB Halts Review of Union Pacific-Norfolk Southern Merger, Sets July 27 Deadline for More Data

The U.S. Surface Transportation Board (STB) has accepted Union Pacific and Norfolk Southern’s $72 billion merger application but paused its review pending additional information, giving the companies until July 27 to address competition and public-benefit concerns.

Shares of both railroads plummeted—Union Pacific dropped as much as 5.2% and Norfolk Southern as much as 6.5%—marking their steepest intraday declines since April 2025. The STB’s decision follows its March request for further documentation on the deal’s competitive impact and public interest benefits, a requirement stricter than those for mergers in other industries.

Union Pacific’s initial application was rejected in January for being insufficient. The proposed merger would create North America’s largest rail network, spanning 43 states, with the companies aiming for a 2027 closure.

Rival BNSF Railway Co. and U.S. lawmakers have already raised objections, adding to the regulatory hurdles.