Union Pacific and Norfolk Southern could announce a tentative merger agreement as early as this week, according to a published report. Bloomberg cited sources familiar with the talks in its report on Friday.

The combination of two large rail companies would create the first coast-to-coast network, but the deal could reduce competition.

(UP) and Norfolk Southern Corp., major grain shippers and two of the six Class I freight railroads in North America, confirmed they are in “advanced discussions” regarding a potential merger. “There can be no assurances as to whether an agreement for a transaction will be reached or as to the terms of any such transaction,