No date has been set for an end to the investigation, according to Bloomberg.

Herb Kohl, chairman of the U.S. Senate's Antitrust subcommittee, on Thursday warned Congress to be wary of the deal, Wired News reported.

“Should the amount of advertising outsourced by Yahoo to Google grow significantly, we believe the threat to competition will also increase,” Kohl stated in a letter to Congress, according to Wired.