AT&T and the US Department of Justice (DoJ) prepared to face off in court for the first time as part of antitrust proceedings relating to the operator’s $85.4 billion bid to acquire Time Warner.

In an initial proceeding today (7 December), the company and DoJ are expected to duke it out over the start date for a full hearing on the case. An AT&T court filing in November called for the trial to begin as soon as possible with a 20 February start date requested.

This immediately put the operator at odds with the DoJ, which pushed for a start date of 7 May.

AT&T urged the court in its filing to go with the earlier date, noting the DoJ spent more than a year investigating the Time Warner transaction before taking legal action. The operator added it provided the DoJ with nearly 25 million pages of documentation from more than 100 different sources and 200 pages of query responses as part of the regulator’s investigation so far.

At stake for AT&T is $500 million, which the operator will be forced to pay Time Warner if the deal isn’t wrapped up by a 22 April deadline.

The transaction was originally scheduled to close in October, but both companies agreed to extend the deadline to await approval from US regulators.