NEW YORK ( TheStreet) -- Entergy ( ETR - Get Report) plans to divest and then merge its electric transmission business with ITC Holdings ( ITC), making ITC one of the largest U.S. electric transmission companies. Entergy's electric transmission business has 15,700 miles of interconnected transmission lines. In the deal, Entergy will divest this business into a newly created entity called Mid South TransCo, which will then merge into a newly formed subsidiary of ITC. Entergy's stockholders will receive shares of the new company. Entergy shareholders will have a 50.1% stake in the new company. The transaction is expected to be completed around the end of 2013. Entergy anticipates getting about $1.78 billion from the deal. Shares of both companies were rising in premarket trading Monday. Entergy rose 3.5% to $72.10 and ITC gained 5.7% to $78.01. -- Written by Alexandra Zendrian >To contact the writer of this article, click here: Alexandra Zendrian >To submit a news tip, send an email to: firstname.lastname@example.org. >To follow the writer on Twitter, go to Alexandra Zendrian.