Shares of Union Pacific Corp. and Norfolk Southern Corp. slumped the most in more than a year after a key regulator paused its review of their planned $72 billion merger, potentially delaying what would be the biggest rail deal ever.
Shares of Union Pacific Corp. and Norfolk Southern Corp. slumped the most in more than a year after a key regulator paused its review of their planned $72 billion merger, potentially delaying what would be the biggest rail deal ever.