Omnicom and Publicis have passed the waiting period for the federal Hart-Scott-Rodino Improvement Acts, which means Uncle Sam does not object to the merger to create an ad/PR firm colossus with annual revenues of $23B.

Publicis and Omnicom said today in a joint statement: ‘The expiration of the HSR review period in the U.S. and the approvals received in other jurisdictions satisfy some of the conditions necessary for the transaction to close.”

Regulatory agencies in Canada, India, South Korea, South Africa and Turkey also have okayed the transaction.

The firms noted “the merger is also subject to additional global regulatory” and approval of shareholders from both companies.

The deal to unite OMC’s Ketchum, Porter Novelli, FleishmanHillard, Cone Communications, Kreab Gavin Anderson, Brodeur and Mercury with Publicis’ MSLGroup, Publicis Consultants and Kekst  is expected to be completed in 2014.