OMNICOM GROUP INC.

NOTES:

1. Net Income and Net Income per Share for Omnicom Group Inc.

2. See Non-GAAP reconciliations starting on page 9.

3. For the three months ended September 30, 2026, operating expenses included $84.7 million ($63.5 million after-tax) of repositioning costs, primarily related to real estate and other exit charges, in connection with the Merger. For the nine months ended September 30, 2026, operating expenses included $135.8 million ($101.8 million after-tax) of repositioning costs, primarily related to real estate and other exit charges, as well as severance charges, in connection with the Merger. For the three and nine months ended September 30, 2026, operating expenses included $106.8 million ($69.5 million after-tax) and $72.5 million ($41.7 million after-tax), respectively, of net gains on dispositions of certain businesses in connection with the Merger. In addition, included in selling, general and administrative expenses for the three and nine months ended September 30, 2026, are integration related costs of $40.4 million ($13.3 million after-tax) and $139.9 million ($98.1 million after-tax), respectively, related to the Merger. The net impact of these items reduced operating income for the three and nine months ended September 30, 2026, by $18.3 million ($7.3 million after-tax) and $203.2 million ($158.2 million after-tax), respectively, which reduced diluted net income per share - Omnicom Group Inc. by $0.03 and $0.55, respectively.

For the three and nine months ended September 30, 2025, operating expenses included $38.6 million ($28.4 million after-tax) of repositioning costs, primarily related to severance actions as we prepared to integrate IPG. For the nine months ended September 30, 2025, operating expenses included $127.4 million ($95.7 million after-tax) of repositioning costs, related to severance actions as we prepared for the acquisition of IPG, as well as efficiency initiatives in the second quarter of 2025, primarily within the Omnicom Advertising and Omnicom Production. In addition, included in selling, general and administrative expenses for the three and nine months ended September 30, 2025, are acquisition related costs of $60.8 million ($50.8 million after-tax) and $160.6 million ($145.0 million after-tax), respectively, related to the Merger. The net impact of these items reduced operating income for the three and nine months ended September 30, 2025 by $99.4 million ($79.2 million after-tax) and $288.0 million ($240.7 million after-tax), respectively, which reduced diluted net income per share - Omnicom Group Inc. by $0.41 and $1.23, respectively.

4. We define EBITA as earnings before interest, taxes and amortization, principally of acquired intangible assets and internally developed strategic platform assets.

5. Combined (OMC + IPG) represents combined results from Omnicom and IPG as previously reported on a separate company basis during the prior year period. Amounts for 2025 are calculated on a combined basis for Omnicom and IPG. These amounts are the arithmetic sum of each company's historical reported results, sourced from either Omnicom's Form 8-K filed on October 21, 2025 or IPG's Form 10-Q filed on November 10, 2025, and have not been prepared in accordance with Article 11 of Regulation S-X, do not reflect any pro forma adjustments, and are not necessarily indicative of the results that would have been achieved had the Merger been completed at the beginning of the periods presented. Any pro forma adjustments in conformity with Article 11 would not be material to the combined amounts presented.

6. Core Operations: calculated from the consolidated revenue, adjusted operating income and adjusted EBITA of Omnicom, excluding businesses that have been disposed of or are classified as held for sale. Dispositions and held for sale, includes 2025 pre acquisition results for all businesses designated as assets held for sale and includes 2026 results for all business designated as held for sale for which the dispositions have not yet been completed, and for completed dispositions for the portion of the period prior to their disposition date.