Citing two people familiar with the situation, Bloomberg reported that the Justice Departments antitrust division also has sent civil investigation demands that resemble subpoenas to competitors of AT&T and T-Mobile USA, seeking data concerning how the merger might affect their businesses.
The second round of requests will allow the Justice Department to extend its review of the merger indefinitely, according to the report.
The Federal Communications Commission also is reviewing AT&Ts $39 billion acquisition of T-Mobile USA, and the companies have filed hundreds of pages of documents with the FCC that are available for public inspection. The documents filed with the Justice Department are not available for public inspection.
The Justice Department and Federal Trade Commission examine large mergers under federal antitrust law to determine impacts on competition and related factors such as whether a transaction will lead to higher prices.
The FCC will review AT&Ts planned acquisition under a broader standard to ascertain whether the merger is in the public interest. The FCCs analysis also considers a mergers effects on competition, among other impacts.
U.S. regulators are likely to impose significant conditions on the merger. The federal government also could move to block the transaction in court, as the Justice Department did more than a decade ago to prevent the $129 billion marriage of WorldCom and Sprint.
In documents filed with the FCC, AT&T has said the U.S. wireless industry is among the most competitive markets in the nation and will remain so after it acquires T-Mobile USA, a Bellevue, Wash.-based subsidiary of Deutsche Telekom.
But critics of the merger assert that the transaction will eliminate one of the nations largest competitors, further concentrating power in the hands of only a few companies.
AT&T and Verizon Wireless will control nearly 80 percent of all U.S. mobile subscribers if federal regulators give AT&T permission to buy T-Mobile USA, according to some industry observers.