A proposed $85 billion mega-merger between Union Pacific and Norfolk Southern has hit a speed bump, after regulators rejected the application as incomplete.

The U.S. Surface Transportation Board (STB) issued a unanimous 15-page decision on January 16, which cited a lack of projected market-share data for the proposed merger, and the failure of the two companies to include the complete agreement in their application. However, the STB also noted that UP and Norfolk can still re-submit, and that the decision to reject the initial application does not necessarily indicate how the board might ultimately rule on the deal.

Moving forward, UP and Norfolk Southern will have until February 17 to notify the board of their intention to file an updated application, and will have to submit that application by June 22. In a statement to Trains magazine, UP said that it plans to provide the additional information requested by the board. 

Other railways had voiced concerns over a lack of transparency from UP and Norfolk Southern in the lead-up to the STB's decision. In a January 12 statement, CN Railway announced that it had filed a motion with the board, alleging that UP and Norfolk had not been upfront with their assessment of the merger, and pointing to several potential issues with the two companies' application. 

“Given the scale and stakes of the proposed combination, the applicants must meet the highest standard of transparency and compliance," said CN senior VP and chief legal officer Olivier Chouc. "The information the applicants refuse to disclose is critical to understand their perspective on anticipated competitive harms and inform the board’s public-interest and competition analyses."