The U.S. Department of Justice has signed off on both proposed major stock exchange mergers in the United States.

The New York Stock Exchange and Archipelago Holdings Inc. announced that the Department of Justice Antitrust Division has completed its review of the NYSE/Archipelago merger. “This brings us one step closer to closing this important transaction,” they said.

At the same time, the Nasdaq Stock Market Inc. announced that it has been informed by the DOJ that it will not oppose the planned acquisition of Instinet Group Inc.

Nasdaq president and CEO Robert Greifeld said, “We are grateful for the thorough review of this significant transaction by the Department of Justice and look forward to closing our acquisition of INET. The combination of Nasdaq and INET will produce an enhanced trading platform for Nasdaq that will allow us to compete vigorously with domestic and international exchanges for both trading and listings. The acquisition will help Nasdaq to innovate and to ‘raise the bar’ for the capital markets, with the ultimate goal of providing better execution quality and cost efficiencies for all investors.”

The combination of Nasdaq with the INET ECN will provide investors with a technologically superior trading platform that is positioned to compete effectively in a post-Regulation NMS environment, it adds. Nasdaq says it expects to realize significant savings with the help of the INET technology. It also expects the transaction to reduce clearing costs and corporate expenses associated with the combined entity. Nasdaq anticipates this transaction will be accretive to Nasdaq shareholders within 12 months of closing.