UPDATED: The Department of Justice’s Antitrust Division and the Federal Trade Commission made the announcement today. Justice is filing a civil suit against Comcast’s Brian Roberts, but with the proposed settlement agreement that includes the fine. Officials went after him because this is the third time Roberts failed to report that he had been granted stock above a government-set threshold that required him to make an official disclosure. The question is: How could a company that employs so many high-priced lawyers be so sloppy?

Still, the Federal Trade Commission — which brought the case to the Justice Department — says that it only sought a modest fine. It notes that ”the violation was inadvertent and technical; that it was apparently due to faulty advice from outside counsel; that Roberts did not gain financially from the violation; and that he reported the violation promptly once it was discovered.” Comcast says that executives “take very seriously our obligations to comply with all aspects of the Hart-Scott-Rodino Act and working with our lawyers we have put in place additional safeguards to ensure that an inadvertent violation does not occur in the future.” Here’s the DOJ release announcing the fine:

WASHINGTON – Comcast Corporation’s CEO Brian L. Roberts will pay a $500,000 civil penalty to settle charges that he violated premerger reporting and waiting requirements when he acquired Comcast voting securities, the Department of Justice announced today.

The Justice Department’s Antitrust Division, at the request of the Federal Trade Commission, filed a civil antitrust lawsuit today in U.S. District Court in Washington, D.C., against Roberts for violating the notification requirements of the Hart-Scott-Rodino (HSR) Act of 1976.  At the same time, the department filed a proposed settlement that, if approved by the court, will settle the charges.

Roberts is also chairman of the board of Comcast, a leading provider of cable television services headquartered in Philadelphia.

According to the complaint, Roberts failed to comply with the antitrust premerger notification requirements of the HSR Act before acquiring voting securities of Comcast as part of his compensation as chairman and chief executive officer of Comcast beginning on Oct. 22, 2007, which resulted in his holding more than $119.6 million of Comcast stock. On Aug. 25, 2009, Roberts made a corrective filing for Comcast voting securities he had acquired. Although this is the first time Roberts has been charged with an HSR Act violation, previously he had twice made corrective filings regarding transactions that he acknowledged were reportable under the HSR Act, asserting that the failures to file and observe the waiting period were inadvertent.

The Hart-Scott-Rodino Act of 1976, an amendment to the Clayton Act, imposes notification and waiting period requirements on individuals and companies over a certain size before they consummate acquisitions resulting in holding stock or assets above a certain value, which was $59.8 million in 2007 and is currently $66 million.

Federal courts can assess civil penalties for premerger notification violations under the HSR Act in lawsuits brought by the Department of Justice. For a party in violation of the HSR Act before Feb. 10, 2009, the maximum civil penalty is $11,000 a day for each day it is in violation of the Act. For a party in violation of the HSR Act on or after Feb. 10, 2009, the maximum penalty is $16,000 a day.