Google Inc. set aside $500 million related to the possible resolution of a U.S. Justice Department investigation of its advertising business, resulting in lower first-quarter profit.

The Justice Department is investigating the use of Google ads by “certain advertisers,” Google said in the filing. Aaron Zamost, a spokesman for the company, declined to comment on the disclosure. Google gets almost all its revenue from online advertising, which runs on its search engine and other sites, such as YouTube.

“Although we cannot predict the ultimate outcome of this matter, we believe it will not have a material adverse effect on our business, consolidated financial position, results of operations or cash flows,” Google said in the statement.

You can find the actual SEC filing here.

Page 29 of the 10-Q, reads:

 

Charge Related to Potential Resolution of Department of Justice Investigation

In May 2011, in connection with a potential resolution of an investigation by the United States Department of Justice into the use of Google advertising by certain advertisers, we accrued $500 million for the three month period ended March 31, 2011. Although we cannot predict the ultimate outcome of this matter, we believe it will not have a material adverse effect on our business, consolidated financial position, results of operations, or cash flows.