NEW YORK—Omnicom, the owner of PR agencies FleishmanHillard, Ketchum and Porter Novelli, grew its PR revenues by 4.6 percent in the third quarter of this year.

The group's third quarter results, reported today, revealed that PR revenues reached $332.5m during the quarter, marking a healthy six percent uptick on the same period one year, earlier. On a like-for-like basis, excluding acquisitions and currency changes, PR income grew by 4.6 percent.

For the year to date, Omnicom's PR earnings have grown by 3.4 percent to $987m. The group's PR revenues were up 2.9 percent in the first half of 2013.

Earlier this year, it was announced that Omnicom and Publicis Groupe are to merge, creating the world's largest holding company and the largest collection of PR operations. According to the results, Omnicom incurred $28.1m of pre-tax expenses in connection with the proposed merger, primarily comprised of professional fees.

The group's PR firms compared well to their ad agency siblings, which increased revenue by 4.8 percent during the third quarter of the year, and Omnicom's CRM shops, which were up by 2.3 percent. However, Omnicom's speciality communications agencies led growth with an 8.3 percent improvement.