Verso Paper Corp. on Wednesday announced it had completed its acquisition of larger rival NewPage Holdings in a deal worth $1.4 billion.

The U.S. Department of Justice gave the deal a green light Dec. 31.

Two Maine paper mills are involved in the deal: Verso’s mill in Jay and the former NewPage mill in Rumford. Because of antitrust issues stemming from concerns that a merged company would control roughly 50 percent of the market for glossy paper in North America, the justice department required that the new Verso sell off the NewPage mill in Rumford. A deal to sell the Rumford mill, which employs roughly 700, to Canadian company Catalyst Paper Corp. was announced in October. The Verso mill in Jay, which employs roughly 850 people, will be unaffected.

Verso said on Wednesday that with completion of the deal it would also change its name from Verso Paper Corp. to just Verso Corp., signifying the company’s plans to diversify beyond paper products to remain viable, according to a news release.

The deal was one year in the making. Verso and NewPage announced their intentions to merge on Jan. 6, 2014. With the completion of the NewPage acquisition, Verso will have approximately $3.5 billion in annual sales and approximately 5,800 employees in eight mills across six states.

“The combination of Verso and NewPage creates a stronger, more stable company with an effective strategy to weather industry headwinds and reduce operating costs, while ensuring our customers continue to benefit from the distinctive quality and service that they have come to expect from us,” David J. Paterson, Verso’s CEO, said in a statement. “We continue to face increased competition from electronic substitution for print and from international producers, but as a larger, more efficient organization with a sustainable capital structure, we are better positioned to deliver solid results despite the industry’s continuing challenges.”

Investors welcomed Verso’s acquisition of NewPage. Verso’s stock has increased 414 percent since the deal was first announced a year ago, rising from just $0.65 on Jan. 6, 2014, to a closing price of $3.34 Wednesday.