Management Presentation Fourth Quarter & Full Year 2020 Results March 2, 2021

2 This presentation contains forward-looking statements. Statements in this presentation that are not historical facts, including without limitation the information under the heading "Financial Outlook" and statements about the Company’s beliefs and expectations, earnings (loss) guidance, recent business and economic trends, potential acquisitions, and estimates of amounts for redeemable noncontrolling interests and deferred acquisition consideration, constitute forward-looking statements. Words such as “estimates”, “expects”, “contemplates”, “will”, “anticipates”, “projects”, “plans”, “intends”, “believes”, “forecasts”, “may”, “should”, and variations of such words or similar expressions are intended to identify forward-looking statements. These statements are based on current plans, estimates and projections, and are subject to change based on a number of factors, including those outlined in this section. Forward-looking statements speak only as of the date they are made, and the Company undertakes no obligation to update publicly any of them in light of new information or future events, if any. Forward-looking statements involve inherent risks and uncertainties. A number of important factors could cause actual results to differ materially from those contained in any forward-looking statements. Such risk factors include, but are not limited to, the following: • risks associated with international, national and regional unfavorable economic conditions that could affect the Company or its clients, including as a result of the novel coronavirus pandemic (“COVID-19”); • the effects of the outbreak of COVID-19, including the measures to reduce its spread, and the impact on the economy and demand for our services, which may precipitate or exacerbate other risks and uncertainties; • an inability to realize expected benefits of the proposed redomiciliation of the Company from the federal jurisdiction of Canada to the State of Delaware (the “Redomiciliation”) and the subsequent combination of the Company’s business with the business of the subsidiaries of Stagwell Media LP (“Stagwell”) that own and operate a portfolio of marketing services companies (the “Business Combination” and, together with the Redomiciliation, the “Proposed Transactions”) or the occurrence of difficulties in connection with the Proposed Transaction; • adverse tax consequences in connection with the Proposed Transactions for the Company, its operations and its shareholders, that may differ from the expectations of the Company, including that future changes in tax law, potential increases to corporate tax rates in the United States and disagreements with the tax authorities on the Company’s determination of value and computations of its tax attributes may result in increased tax costs; • the occurrence of material Canadian federal income tax (including material “emigration tax”) as a result of the Proposed Transactions; • the impact of uncertainty associated with the Proposed Transactions on the Company’s businesses; • direct or indirect costs associated with the Proposed Transactions, which could be greater than expected; • the risk that a condition to completion of the Proposed Transactions may not be satisfied and the Proposed Transactions may not be completed; • the risk of parties challenging the Proposed Transactions or the impact of the Proposed Transactions on the Company’s debt arrangements; • the Company’s ability to attract new clients and retain existing clients; • reduction in client spending and changes in client advertising, marketing and corporate communications requirements; • financial failure of the Company’s clients; • the Company’s ability to retain and attract key employees; FORWARD LOOKING STATEMENTS & OTHER INFORMATION

3 • the Company’s ability to achieve the full amount of its stated cost saving initiatives; • the Company’s implementation of strategic initiatives; • the Company’s ability to remain in compliance with its debt agreements and the Company’s ability to finance its contingent payment obligations when due and payable, including but not limited to those relating to redeemable noncontrolling interests and deferred acquisition consideration; • the successful completion and integration of acquisitions which complement and expand the Company’s business capabilities; and • foreign currency fluctuations. Investors should carefully consider these risk factors and the additional risk factors outlined in more detail in the Company's Annual Report on Form 10-K and in the Company’s other SEC filings. . FORWARD LOOKING STATEMENTS & OTHER INFORMATION (Cont.)

4 • Sequential revenue growth of 15.8% from the third quarter of 2020 • Organic revenue decline of 13.7% in the fourth quarter and 13.9% YTD, driven by lower spending by clients in connection with the COVID-19 pandemic • Adjusted EBITDA Margin in 2020 was 14.8%, vs. 12.3% in the prior year, an increase of 250 basis points • Net New Business wins of $29.5 million in the fourth quarter and $90.3 million in 2020 • Covenant EBITDA (LTM) of $190.1 million as of the end of the fourth quarter of 2020 versus $180.5 million as of the end of the fourth quarter of 2019, an improvement of 5.3% • Adjusted EBITDA of $177.3 million in 2020 versus $174.2 million in the prior year, an increase of 1.8%. Adjusted EBITDA Margin of 14.8% in 2020, compared with 12.3% in the prior year SUMMARY Note: See appendix for definitions of Non-GAAP Financial Measures

5 • Revenue of $328.2 million versus $382.0 million in the prior year period • Sequential revenue growth of 15.8% from the third quarter of 2020 • Organic revenue decreased by 13.7% versus the prior year period. Organic revenue was unfavorably impacted by 63 basis points from billable pass through costs • Adjusted EBITDA of $47.5 million versus $57.0 million in the prior year period, a decrease of 16.6% • Sequential Adjusted EBITDA decline of 12.0% from the third quarter of 2020, decreasing from $54.1 million to $47.5 million • Adjusted EBITDA Margin of 14.5% vs. 14.9% in the prior year, a decrease of 40 basis points • Covenant EBITDA (LTM) of $190.1 million for the fourth quarter of 2020 versus $180.5 million for the fourth quarter of 2019, an increase of 5.3% • Net new business wins of $29.5 million Note: See appendix - "Definitions of Non-GAAP Financial Measures". FORTH QUARTER 2020 FINANCIAL HIGHLIGHTS

6 • Revenue of $1.20 billion versus $1.42 billion for the prior year period • Organic revenue decreased by 13.9% versus the prior year period. Organic revenue was unfavorably impacted by 162 basis points from billable pass through costs • Adjusted EBITDA of $177.3 million versus $174.2 million for the prior year period, an increase of 1.8% • Adjusted EBITDA Margin of 14.8% vs. 12.3% in the prior year, an increase of 250 basis points • Excluding Kingsdale and Sloane, Adjusted EBITDA increased 5.2% in 2020 compared with the prior year period • Net New Business wins of $90.3 million Note: See appendix - "Definitions of Non-GAAP Financial Measures". TWELVE MONTHS 2020 FINANCIAL HIGHLIGHTS

7 (US$ in millions, except percentages) Three Months Ended December 31, Twelve Months Ended December 31, 2020 2019 % Change 2020 2019 % Change Revenue: $ 328.2 $ 382.0 (14.1) % $ 1,199.0 $ 1,415.8 (15.3) % Operating Expenses: Cost of services sold 209.0 260.7 (19.8) % 769.9 961.1 (19.9) % Office and general expenses 136.5 94.2 44.9 % 341.6 328.3 4.0 % Depreciation and amortization 9.5 9.5 0.1 % 36.9 38.3 (3.7) % Impairment and other losses 77.2 6.7 NM 96.4 8.6 NM Operating income (loss) (104.1) 10.9 NM (45.8) 79.5 NM Interest expense and finance charges, net (15.3) (15.7) (62.2) (64.9) Foreign exchange gain (loss) 6.3 4.3 (1.0) 8.8 Other, net (2.2) 2.2 20.5 (2.4) Income tax expense 109.5 4.0 116.6 10.3 Equity in earnings (losses) of non-consolidated affiliates (1.4) — (2.2) 0.4 Net income (loss) (226.3) (2.3) (207.2) 10.9 Net income attributable to the noncontrolling interest (7.2) (5.4) (21.8) (16.2) Accretion on and net income allocated to convertible preference shares (3.7) (3.4) (14.2) (12.3) Net loss attributable to MDC Partners Inc. common shareholders $ (237.1) $ (11.1) $ (243.2) $ (17.6) CONSOLIDATED REVENUE AND EARNINGS Note: Actuals may not foot due to rounding Note: See appendix for definitions of Non-GAAP Financial Measures

8 Organic revenue declined 13.7% in the fourth quarter and 13.9% YTD versus the prior year period. (US$ in millions, except percentages) Three Months Ended Twelve Months Ended Revenue $ % Change Revenue $ % Change December 31, 2019 $ 382.0 $ 1,415.8 Organic revenue (52.2) (13.7) % (197.5) (13.9) % Non-GAAP acquisitions (dispositions), net (4.4) (1.2) % (18.3) (1.3) % Foreign exchange impact 2.8 0.7 % (1.0) (0.1) % Total Change (53.8) (14.1) % (216.8) (15.3) % December 31, 2020 $ 328.2 $ 1,199.0 REVENUE SUMMARY Note: Actuals may not foot due to rounding

9 REVENUE BY GEOGRAPHY AND SEGMENT (1) (US$ in millions, except percentages) 2020 Q1 Q2 Q3 Q4 Total Total Organic Revenue Total Total Organic Revenue Total Total Organic Revenue Total Total Organic Revenue Revenue Growth Growth (Decline) Revenue Growth Growth (Decline) Revenue Growth Growth (Decline) Revenue Growth Growth (Decline) United States $ 264.6 0.6 % 1.3 % $ 210.3 (26.1) % (24.7) % $ 228.3 (16.0) % (14.5) % $ 256.5 (13.6) % (12.1) % Canada 18.3 18.4 % (1.7) % 16.6 (32.4) % (28.9) % 20.3 (21.6) % (20.9) % 26.8 (17.0) % (18.4) % North America 282.8 0.9 % 1.1 % 227.0 (26.6) % (25.0) % 248.6 (16.5) % (15.0) % 283.2 (13.9) % (12.7) % Other 44.9 3.5 % 7.6 % 32.7 (38.1) % (34.2) % 34.9 (23.1) % (25.4) % 44.9 (15.3) % (19.8) % Total $ 327.7 (0.3) % 2.0 % $ 259.7 (28.3) % (26.4) % $ 283.4 (17.3) % (16.4) % $ 328.2 (14.1) % (13.7) % Integrated Networks - Group A $ 90.6 22.9 % 23.4 % $ 82.7 (19.9) % (19.2) % $ 87.1 (12.3) % (12.7) % $ 119.2 2.9 % 2.3 % Integrated Networks - Group B 117.7 (11.6) % (11.0) % 93.4 (30.0) % (29.0) % 112.2 (13.1) % (12.8) % 112.3 (17.5) % (17.7) % Media & Data Network 41.1 (5.0) % (4.5) % 28.6 (27.6) % (26.7) % 33.6 (7.3) % (7.3) % 35.8 (15.7) % (16.1) % All Other 78.4 (0.4) % 7.3 % 55.0 (36.1) % (30.7) % 50.6 (35.4) % (31.2) % 60.8 (30.6) % (27.3) % Total $ 327.7 (0.3) % 2.0 % $ 259.7 (28.3) % (26.4) % $ 283.4 (17.3) % (16.4) % $ 328.2 (14.1) % (13.7) % (1) Effective in the first quarter of 2020, the Company reorganized its management structure resulting in the aggregation of certain Partner Firms into integrated groups (“Networks”). In connection with our discussions with the SEC, the Company has changed the prior presentation for the Networks. Beginning in the second quarter of 2020, the Company separated the Networks into two reportable segments: Integrated Networks - Group A and Integrated Networks - Group B. Prior periods presented have been recast to reflect the change in reportable segments. Note: Actuals may not foot due to rounding

10 REVENUE BY GEOGRAPHY AND SEGMENT (1) (US$ in millions, except percentages) 2019 Q1 Q2 Q3 Q4 Total Total Organic Revenue Total Total Organic Revenue Total Total Organic Revenue Total Total Organic Revenue Revenue Growth Growth (Decline) Revenue Growth Growth (Decline) Revenue Growth Growth (Decline) Revenue Growth Growth (Decline) United States $ 263.0 2.5 % (1.7) % $ 284.7 (3.6) % (3.8) % $ 271.7 (8.4) % (8.5) % $ 296.7 (2.4) % (2.4) % Canada 22.4 (15.2) % (3.8) % 24.6 (25.8) % (5.6) % 25.9 (19.4) % (7.0) % 32.2 (0.5) % 12.6 % North America 285.4 0.9 % (1.9) % 309.2 (5.8) % (3.9) % 297.6 (9.5) % (8.3) % 328.9 (2.2) % (0.9) % Other 43.4 (1.5) % 5.4 % 52.9 3.0 % 7.3 % 45.3 (3.8) % (1.5) % 53.0 (5.4) % (3.0) % Total $ 328.8 0.6 % (0.9) % $ 362.1 (4.6) % (2.4) % $ 342.9 (8.8) % (7.5) % $ 382.0 (2.7) % (1.2) % Integrated Networks - Group A $ 73.7 (13.3) % (12.7) % $ 103.2 7.2 % 8.2 % $ 99.3 (2.0) % (1.4) % $ 115.8 4.1 % 4.2 % Integrated Networks - Group B 133.2 14.4 % 7.1 % 133.4 (10.3) % (9.9) % 129.1 (11.3) % (10.8) % 136.1 (3.3) % (2.9) % Media & Data Network 43.2 (4.6) % (3.5) % 39.5 (9.2) % (8.3) % 36.2 (21.0) % (20.6) % 42.5 (12.5) % (12.6) % All Other 78.6 (1.9) % 1.6 % 86.0 (5.8) % 1.4 % 78.3 (5.8) % (1.9) % 87.5 (4.8) % 0.8 % Total $ 328.8 0.6 % (0.9) % $ 362.1 (4.6) % (2.4) % $ 342.9 (8.8) % (7.5) % $ 382.0 (2.7) % (1.2) % (1) Effective in the first quarter of 2020, the Company reorganized its management structure resulting in the aggregation of certain Partner Firms into integrated groups (“Networks”). In connection with our discussions with the SEC, the Company has changed the prior presentation for the Networks. Beginning in the second quarter of 2020, the Company separated the Networks into two reportable segments: Integrated Networks - Group A and Integrated Networks - Group B. Prior periods presented have been recast to reflect the change in reportable segments. Note: Actuals may not foot due to rounding

11 (US$ in millions, except percentages) Three Months Ended December 31 2020 2019 Total Total Organic Revenue Total Total Organic Revenue Revenue Growth Growth (Decline) Revenue Growth Growth (Decline) United States $ 256.5 (13.6) % (12.1) % $ 296.7 (2.4) % (2.4) % Canada 26.8 (17.0) % (18.4) % 32.2 (0.5) % 12.6 % North America 283.3 (13.9) % (12.7) % 328.9 (2.2) % (0.9) % Other 44.9 (15.3) % (19.8) % 53.0 (5.4) % (3.0) % Total $ 328.2 (14.1) % (13.7) % $ 382.0 (2.7) % (1.2) % Integrated Networks - Group A $ 119.2 2.9 % 2.3 % $ 115.8 4.1 % 4.2 % Integrated Networks - Group B 112.3 (17.5) % (17.7) % 136.1 (3.3) % (2.9) % Media & Data Network 35.8 (15.7) % (16.1) % 42.5 (12.5) % (12.6) % All Other 60.8 (30.6) % (27.3) % 87.5 (4.8) % 0.8 % Total $ 328.2 (14.1) % (13.7) % $ 382.0 (2.7) % (1.2) % REVENUE BY GEOGRAPHY AND SEGMENT (1) (1) Effective in the first quarter of 2020, the Company reorganized its management structure resulting in the aggregation of certain Partner Firms into integrated groups (“Networks”). In connection with our discussions with the SEC, the Company has changed the prior presentation for the Networks. Beginning in the second quarter of 2020, the Company separated the Networks into two reportable segments: Integrated Networks - Group A and Integrated Networks - Group B. Prior periods presented have been recast to reflect the change in reportable segments. Note: Actuals may not foot due to rounding

12 (US$ in millions, except percentages) Twelve Months Ended December 31, 2020 2019 Total Total Organic Revenue Total Total Organic Revenue Revenue Growth Growth (Decline) Revenue Growth Growth (Decline) United States $ 959.6 (14.0) % (12.7) % $ 1,116.0 (3.2) % (4.1) % Canada 81.9 (22.0) % (17.9) % 105.1 (15.3) % (0.9) % North America 1,041.6 (14.7) % (13.2) % 1,221.1 (4.3) % (3.8) % Other 157.4 (19.1) % (18.9) % 194.7 (2.0) % 1.9 % Total $ 1,199.0 (15.3) % (13.9) % $ 1,415.8 (4.0) % (3.1) % Integrated Networks - Group A $ 379.6 (3.2) % (3.2) % $ 392.1 (0.5) % — % Integrated Networks - Group B 435.6 (18.1) % (17.7) % 531.7 (3.6) % (4.8) % Media & Data Network 139.0 (13.9) % (13.6) % 161.5 (11.9) % (11.3) % All Other 244.8 (26.0) % (20.9) % 330.5 (4.6) % 0.5 % Total $ 1,199.0 (15.3) % (13.9) % $ 1,415.8 (4.0) % (3.1) % REVENUE BY GEOGRAPHY AND SEGMENT (1) (1) Effective in the first quarter of 2020, the Company reorganized its management structure resulting in the aggregation of certain Partner Firms into integrated groups (“Networks”). In connection with our discussions with the SEC, the Company has changed the prior presentation for the Networks. Beginning in the second quarter of 2020, the Company separated the Networks into two reportable segments: Integrated Networks - Group A and Integrated Networks - Group B. Prior periods presented have been recast to reflect the change in reportable segments. Note: Actuals may not foot due to rounding

13 Top 10 clients made up 21.0% of revenue in 2020, a decrease from 23.4% in 2019. (Largest < 3.6%) REVENUE BY CLIENT INDUSTRY Q4 2020 QTD 2020 YTD Above 10% Consumer Products - 0% to 10% Retail, Healthcare Healthcare Below 0% Automotive, Technology, Food and Beverage, Communications, Financials, Transportation and Travel/Lodging, Other Technology, Consumer Products, Communications, Financials, Transportation and Travel/Lodging, Food and Beverage, Retail, Automotive, Other Year-over-Year Growth by CategoryQ4 2020 Mix Other 9% Food & Beverage 16% Communications 6% Retail 12% Consumer Products 16% Healthcare 9% Financials 8% Technology 16% Automotive 5% Transportation and Travel/Lodging 3%

14 ADJUSTED EBITDA (1) (US$ in millions, except percentages) % Change 2019 2020 Q4 2020 vs. Q4 2019 Q4 Q1 Q2 Q3 Q4 Integrated Networks - Group A 31.7 16.3 17.2 21.0 25.3 (20.2) % Integrated Networks - Group B 19.5 17.1 16.4 29.6 21.2 8.7 % Media & Data Network 5.4 1.8 0.9 3.0 4.0 (25.9) % All Other 10.7 9.9 6.9 7.1 6.8 (36.4) % Corporate Group (10.1) (5.6) (5.2) (6.7) (9.7) (4.0) % Adjusted EBITDA (2) $ 57.0 $ 39.6 $ 36.2 $ 54.1 $ 47.5 (16.6) % Adjusted EBITDA margin 14.9 % 12.1 % 13.9 % 19.1 % 14.5 % (1) Effective in the first quarter of 2020, the Company reorganized its management structure resulting in the aggregation of certain Partner Firms into integrated groups (“Networks”). In connection with our discussions with the SEC, the Company has changed the prior presentation for the Networks. Beginning in the second quarter of 2020, the Company separated the Networks into two reportable segments: Integrated Networks - Group A and Integrated Networks - Group B. Prior periods presented have been recast to reflect the change in reportable segments. (2)Adjusted EBITDA is a non-GAAP financial measure. See appendix for the definition. Note: Actuals may not foot due to rounding.

15 ADJUSTED EBITDA (1) (US$ in millions, except percentages) Twelve Months Ended December 31, 2020 2019 % Change Integrated Networks - Group A 79.8 74.8 6.7 % Integrated Networks - Group B 84.3 84.6 (0.4) % Media & Data Network 9.7 7.7 26.0 % All Other 30.8 37.6 (18.1) % Corporate Group (27.2) (30.6) (11.1) % Adjusted EBITDA (2) $ 177.3 $ 174.2 1.8 % Adjusted EBITDA margin 14.8 % 12.3 % (1) Effective in the first quarter of 2020, the Company reorganized its management structure resulting in the aggregation of certain Partner Firms into integrated groups (“Networks”). In connection with our discussions with the SEC, the Company has changed the prior presentation for the Networks. Beginning in the second quarter of 2020, the Company separated the Networks into two reportable segments: Integrated Networks - Group A and Integrated Networks - Group B. Prior periods presented have been recast to reflect the change in reportable segments. (2)Adjusted EBITDA is a non-GAAP financial measure. See appendix for the definition. Note: Actuals may not foot due to rounding.

16 COVENANT EBITDA 2020 Covenant EBITDA (LTM) (1) (US$ in millions) Q1 Q2 Q3 Q4 Q4-2020 - LTM Net income (loss) attributable to MDC Partners Inc. common shareholders $ (2.4) $ (4.1) $ 0.4 $ (237.1) $ (243.3) Adjustments to reconcile to operating income (loss): Accretion on and net income allocated to convertible preference shares 3.4 3.5 3.7 3.7 14.3 Net income attributable to the noncontrolling interests 0.8 3.1 10.7 7.2 21.8 Equity in losses of non-consolidated affiliates — 0.8 — 1.4 2.2 Income tax expense (benefit) 13.5 (7.9) 1.5 109.5 116.6 Interest expense and finance charges, net 15.6 15.9 15.3 15.3 62.2 Foreign exchange loss (gain) 14.8 (5.3) (2.2) (6.3) 1.0 Other income, net (16.3) (5.9) (0.5) 2.2 (20.5) Operating income (loss) 29.3 0.1 28.9 (104.1) (45.8) Adjustments to reconcile to Adjusted EBITDA: Depreciation and amortization 9.2 8.9 9.3 9.5 36.9 Impairment and other losses 0.2 18.8 0.2 77.2 96.4 Stock-based compensation 3.1 1.0 6.5 3.6 14.2 Deferred acquisition consideration adjustments (4.6) 2.3 2.8 41.7 42.2 Distributions from non-consolidated affiliates — 1.1 0.2 0.9 2.2 Other items, net (2) 2.4 3.9 6.2 18.7 31.2 Adjusted EBITDA 39.6 36.2 54.1 47.5 177.3 Adjustments to reconcile to Covenant EBITDA: Proforma dispositions (3) (0.1) — — — (0.1) Severance due to eliminated positions 2.1 5.2 2.3 2.0 11.7 Other adjustments, net (4) 0.4 0.2 0.1 0.6 1.2 $ 41.9 $ 41.6 $ 56.5 $ 50.1 $ 190.1 (1) Covenant EBITDA is a measure that includes pro forma adjustments for acquisitions, one-time charges, permitted dispositions and other adjustments, as defined in the Company's Credit Agreement. Covenant EBITDA is calculated as the aggregate of operating results for the rolling last twelve months (LTM). Each quarter is presented to provide the information utilized to calculate Covenant EBITDA. Historical Covenant EBITDA may be re-casted in the current period for any proforma adjustments related to acquisitions and/or dispositions in the current period. See "Non-GAAP Financial Measures" herein. (2) Other items, net includes items such as severance expense, other restructuring expenses and costs associated with the Company's strategic review process. (3) Represents Kingsdale and Sloane EBITDA for the respective period. (4) Other adjustments, net primarily includes one-time professional fees and costs associated with real estate consolidation. Note: Actuals may not foot due to rounding.

17 COVENANT EBITDA 2019 Covenant EBITDA (LTM) (1) (US$ in millions) Q1 Q2 Q3 Q4 Q4-2019 - LTM Net income (loss) attributable to MDC Partners Inc. common shareholders $ (2.5) $ 1.0 $ (5.1) $ (11.1) $ (17.6) Adjustments to reconcile to operating income: Accretion on and net income allocated to convertible preference shares 2.4 3.2 3.3 3.4 12.3 Net income attributable to the noncontrolling interests 0.4 3.0 7.3 5.4 16.2 Equity in (earnings) of non-consolidated affiliates (0.1) (0.2) (0.1) — (0.4) Income tax expense 0.7 2.1 3.5 4.0 10.3 Interest expense and finance charges, net 16.8 16.4 16.1 15.7 64.9 Foreign exchange loss (gain) (5.4) (2.9) 4.0 (4.3) (8.8) Other income, net 3.4 0.7 0.4 (2.2) 2.4 Operating income 15.7 23.4 29.4 10.9 79.5 Adjustments to reconcile to Adjusted EBITDA: Depreciation and amortization 8.8 10.7 9.4 9.5 38.3 Impairment and other losses — — 1.9 6.7 8.6 Stock-based compensation 3.0 3.6 6.0 18.4 31.0 Deferred acquisition consideration adjustments (7.6) 2.1 1.9 9.0 5.4 Distributions from non-consolidated affiliates — — (0.2) 2.2 2.0 Other items, net (2) 1.6 6.6 0.7 0.3 9.3 Adjusted EBITDA 21.5 46.4 49.2 57.0 174.2 Adjustments to reconcile to Covenant EBITDA: Proforma acquisitions/dispositions (3) (2.7) (0.7) (1.0) (1.3) (5.7) Severance due to eliminated positions 1.5 2.3 2.0 3.2 9.1 Other adjustments, net (3) 1.4 1.0 0.2 0.4 3.0 $ 21.7 $ 49.0 $ 50.4 $ 59.3 $ 180.5 (1) Covenant EBITDA is a measure that includes pro forma adjustments for acquisitions, one-time charges, permitted dispositions and other adjustments, as defined in the Company's Credit Agreement. Covenant EBITDA is calculated as the aggregate of operating results for the rolling last twelve months (LTM). Each quarter is presented to provide the information utilized to calculate Covenant EBITDA. Historical Covenant EBITDA may be re-casted in the current period for any proforma adjustments related to acquisitions and/or dispositions in the current period. See "Non-GAAP Financial Measures" herein. (2) Other items, net includes items such as severance expense, other restructuring expenses and costs associated with the Company's strategic review process. (3) Represents Kingsdale EBITDA for the respective period. (4) Other adjustments, net primarily includes one-time professional fees and costs associated with real estate consolidation. Note: Actuals may not foot due to rounding.

18 SUMMARY OF CASH FLOW (US$ in millions) Twelve Months Ended December 31, 2020 2019 Net cash provided by operating activities $ 32.6 $ 86.5 Net cash provided by (used in) investing activities (8.3) 0.1 Net cash used in financing activities (73.4) (11.7) Effect of exchange rate changes on cash, cash equivalents, and cash held in trusts 3.0 — Net increase (decrease) in cash, and cash equivalents $ (46.2) $ 74.9 Change in cash and cash equivalents held in trusts classified within held for sale — (3.3) Change in cash and cash equivalents classified within assets held for sale — 4.4 Net increase (decrease) in cash and cash equivalents (46.2) 76.1 Cash and cash equivalents at beginning of period 106.9 30.9 Cash and cash equivalents at end of period $ 60.8 $ 106.9 Supplemental disclosures: Cash income taxes paid $ 7.9 $ 2.3 Cash interest paid $ 57.8 $ 62.2 Note: Actuals may not foot due to rounding.

19 2021 FINANCIAL OUTLOOK 2020 Outlook Commentary* Organic Revenue Growth We expect approximately 7 to 9% growth in organic revenue. Foreign Exchange Impact, net No estimated impact at this time. Impact of Non-GAAP Acquisitions (Dispositions), net Our current expectations are that the impact of acquisitions, net of disposition activity, will have no material impact on revenue. Adjusted EBITDA The Company expects to complete fiscal year 2021 with approximately $190 million to $200 million of Adjusted EBITDA, approximately 7 to 13% above prior year. * The Company has excluded a quantitative reconciliation with respect to the Company’s 2020 guidance under the “unreasonable efforts” exception in Item 10(e)(1)(i)(B) of Regulation S-K See "Non-GAAP Financial Measures" below for additional information. 2021 Outlook Commentary*

20 APPENDIX

21 REVENUE TRENDING SCHEDULE Note: See appendix - "Definitions of Non-GAAP Financial Measures". Note: Actuals may not foot due to rounding (US$ in thousands, except percentages) 2018 2019 2020 Q1 Q2 Q3 Q4 YTD Q1 Q2 Q3 Q4 YTD Q1 Q2 Q3 Q4 YTD Revenue United States $ 256,524 $ 295,268 $ 296,544 $ 304,063 $ 1,152,399 $ 263,017 $ 284,659 $ 271,671 $ 296,698 $ 1,116,045 $ 264,561 $ 210,342 $ 228,256 $ 256,477 $ 959,636 Canada 26,379 33,086 32,132 32,404 124,001 22,378 24,564 25,895 32,230 105,067 18,256 16,609 20,299 26,766 81,930 North America 282,903 328,354 328,676 336,467 1,276,400 285,395 309,223 297,566 328,928 1,221,112 282,817 226,951 248,555 283,243 1,041,566 Other 44,065 51,389 47,154 56,080 198,688 43,396 52,907 45,341 53,047 194,691 44,925 32,727 34,868 44,925 157,445 Total $ 326,968 $ 379,743 $ 375,830 $ 392,547 $ 1,475,088 $ 328,791 $ 362,130 $ 342,907 $ 381,975 $ 1,415,803 $ 327,742 $ 259,678 $ 283,423 $ 328,168 $ 1,199,011 % of Revenue United States 78.5 % 77.8 % 79.0 % 77.4 % 78.1 % 80.0 % 78.6 % 79.2 % 77.7 % 78.8 % 80.7 % 81.0 % 80.5 % 78.2 % 80.1 % Canada 8.1 % 8.7 % 8.5 % 8.2 % 8.4 % 6.8 % 6.8 % 7.6 % 8.4 % 7.4 % 5.6 % 6.4 % 7.2 % 8.2 % 6.8 % North America 86.6 % 86.5 % 87.5 % 85.7 % 86.5 % 86.8 % 85.4 % 86.8 % 86.1 % 86.2 % 86.3 % 87.4 % 87.7 % 86.4 % 86.9 % Other 13.4 % 13.5 % 12.5 % 14.3 % 13.5 % 13.2 % 14.6 % 13.2 % 13.9 % 13.8 % 13.7 % 12.6 % 12.3 % 13.6 % 13.1 % Total 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % 100.0 % Total Growth % United States (6.6) % (3.0) % 2.4 % 0.4 % (1.6) % 2.5 % (3.6) % (8.4) % (2.4) % (3.2) % 0.6 % (26.1) % (16.0) % (13.6) % (14.0) % Canada (0.3) % 8.2 % 2.3 % (6.4) % 0.7 % (15.2) % (25.8) % (19.4) % (0.5) % (15.3) % (18.4) % (32.4) % (21.6) % (17.0) % (22.0) % North America (6.1) % (2.0) % 2.4 % (0.3) % (1.4) % 0.9 % (5.8) % (9.5) % (2.2) % (4.3) % (0.9) % (26.6) % (16.5) % (13.9) % (14.7) % Other 1.2 % (7.4) % (13.8) % (12.7) % (8.8) % (1.5) % 3.0 % (3.8) % (5.4) % (2.0) % 3.5 % (38.1) % (23.1) % (15.3) % (19.1) % Total (5.1) % (2.8) % 0.0 % (2.3) % (2.5) % 0.6 % (4.6) % (8.8) % (2.7) % (4.0) % (0.3) % (28.3) % (17.3) % (14.1) % (15.3) % Organic Revenue Growth (Decline) % United States (1.8) % (2.1) % 0.7 % (1.2) % (1.1) % (1.7) % (3.8) % (8.5) % (2.4) % (4.1) % 1.3 % (24.7) % (14.5) % (12.1) % (12.7) % Canada (1.1) % (7.6) % 7.5 % 0.5 % (0.1) % (3.8) % (5.6) % (7.0) % 12.6 % (0.9) % (1.7) % (28.9) % (20.9) % (18.4) % (17.9) % North America (1.8) % (2.6) % 1.4 % (1.0) % (1.0) % (1.9) % (3.9) % (8.3) % (0.9) % (3.8) % 1.1 % (25.0) % (15.0) % (12.7) % (13.2) % Other 19.8 % 3.7 % 2.0 % 3.3 % 6.4 % 5.4 % 7.3 % (1.5) % (3.0) % 1.9 % 7.6 % (34.2) % (25.4) % (19.8) % (18.9) % Total 1.0 % (1.7) % 1.5 % (0.3) % 0.1 % (0.9) % (2.4) % (7.5) % (1.2) % (3.1) % 2.0 % (26.4) % (16.4) % (13.7) % (13.9) % Growth % from Foreign Exchange United States 0.0 % 0.0 % 0.0 % 0.0 % 0.0 % 0.0 % 0.0 % 0.0 % 0.0 % (0.0) % 0.0 % (0.0) % 0.0 % 0.0 % 0.0 % Canada 4.3 % 4.0 % (4.3) % (3.8) % (0.2) % (4.7) % (3.4) % (1.1) % 1.0 % (1.9) % (0.1) % (3.4) % (0.7) % 1.4 % (0.6) % North America 0.4 % 0.4 % (0.4) % (0.4) % 0.0 % (0.4) % (0.3) % (0.1) % 0.1 % (0.2) % 0.0 % (0.3) % (0.1) % 0.1 % 0.0 % Other 10.0 % 3.4 % (5.1) % (5.6) % (0.1) % (8.8) % (5.9) % (4.3) % (2.4) % (5.2) % (4.1) % (3.9) % 2.3 % 4.5 % (0.2) % Total 1.6 % 0.8 % (1.1) % (1.2) % 0.0 % (1.6) % (1.1) % (0.6) % (0.3) % (0.9) % (0.5) % (0.8) % 0.3 % 0.7 % (0.1) % Growth % from Acquisitions (Dispositions), net United States (1.5) % 1.1 % 2.3 % 2.9 % 1.2 % 4.2 % 0.2 % 0.1 % (0.1) % 1.0 % (0.8) % (1.4) % (1.5) % (1.5) % (1.3) % Canada 0.0 % 0.0 % 0.0 % 0.0 % 0.0 % (6.6) % (16.8) % (11.3) % (14.1) % (12.5) % (16.6) % 0.0 % 0.0 % 0.0 % (3.5) % North America (1.4) % 1.0 % 2.1 % 2.6 % 1.1 % 3.2 % (1.5) % (1.0) % (1.4) % (0.3) % (2.0) % (1.3) % (1.4) % (1.4) % (1.5) % Other (2.7) % (1.3) % 0.3 % 1.4 % (0.4) % 1.9 % 1.6 % 1.9 % 0.0 % 1.3 % 0.0 % 0.0 % 0.0 % 0.0 % 0.0 % Total (1.5) % 0.6 % 1.8 % 2.4 % 0.9 % 3.0 % (1.1) % (0.6) % (1.2) % (0.1) % (1.7) % (1.1) % (1.2) % (1.2) % (1.3) %

22 ADJUSTED EBITDA TRENDING SCHEDULE (US$ in thousands, except percentages) 2018 2019 2020 Q1 Q2 Q3 Q4 YTD Q1 Q2 Q3 Q4 YTD Q1 Q2 Q3 Q4 YTD PARTNER FIRMS Revenue $326,968 $379,743 $375,830 $392,547 $1,475,088 $328,791 $362,130 $342,907 $381,975 $1,415,803 $327,742 $259,678 $283,423 $328,168 $1,199,011 Operating income (loss) (561) 43,912 20,642 (7,402) 56,591 20,504 40,073 38,532 26,119 125,228 37,667 11,921 43,651 (75,106) 18,133 Depreciation and amortization 12,151 11,543 10,935 10,805 45,434 8,621 10,442 9,176 9,222 37,461 8,974 8,663 9,133 8,755 35,525 Impairment and other losses — — 21,008 63,879 84,887 — — 1,944 5,808 7,752 161 17,710 159 77,240 95,270 Stock-based compensation 3,789 4,382 4,622 964 13,757 4,545 2,442 5,193 16,980 29,160 2,928 763 5,038 2,468 11,197 Deferred acquisition consideration adjustments 2,586 (5,067) 11,003 (8,979) (457) (7,643) 2,073 1,943 9,030 5,403 (4,600) 2,312 2,803 41,672 42,187 Distributions from non-consolidated affiliates — — — — — — — (250) — (250) — — — — — Other items, net — — — — — — — — — — — — — 2,240 2,240 Adjusted EBITDA (1) $ 17,965 $ 54,770 $ 68,210 $ 59,267 $ 200,212 $ 26,027 $ 55,030 $ 56,538 $ 67,159 $ 204,754 $ 45,130 $ 41,369 $ 60,784 $ 57,269 $ 204,552 CORPORATE GROUP Revenue — — — — — — — — — — $ — $ — $ — — — Operating loss (14,072) (13,140) (18,024) (9,921) (55,157) (4,823) (16,631) (9,111) (15,203) (45,768) (8,338) (11,823) (14,762) (28,967) (63,890) Depreciation and amortization 224 160 199 179 762 217 221 192 238 868 232 236 199 713 1,380 Impairment and other losses 2,317 — — — 2,317 — — — 847 847 — 1,129 — — 1,129 Stock-based compensation 1,248 1,221 1,620 570 4,659 (1,573) 1,192 833 1,428 1,880 142 276 1,421 1,143 2,982 Distributions from non-consolidated affiliates 20 11 478 270 779 — 31 48 2,219 2,298 (14) 1,079 208 902 2,175 Other items, net 122 (68) 7,346 479 7,879 1,626 6,594 705 349 9,274 2,416 3,895 6,208 16,485 29,004 Adjusted EBITDA (1) $ (10,141) $ (11,816) $ (8,381) $ (8,423) $ (38,761) $ (4,553) $ (8,593) $ (7,333) $ (10,122) $ (30,601) $ (5,562) $ (5,208) $ (6,726) $ (9,724) $ (27,220) TOTAL Revenue $326,968 $379,743 $375,830 $392,547 $1,475,088 $328,791 $362,130 $342,907 $381,975 $1,415,803 $ 327,742 $ 259,678 $ 283,423 $328,168 $1,199,011 Operating income (loss) (14,633) 30,772 2,618 (17,323) 1,434 15,681 23,442 29,421 10,916 79,460 29,329 98 28,889 (104,073) (45,757) Depreciation and amortization 12,375 11,703 11,134 10,984 46,196 8,838 10,663 9,368 9,460 38,329 9,206 8,899 9,332 9,468 36,905 Impairment and other losses 2,317 — 21,008 63,879 87,204 — — 1,944 6,655 8,599 161 18,839 159 77,240 96,399 Stock-based compensation 5,037 5,603 6,242 1,534 18,416 2,972 3,634 6,026 18,408 31,040 3,070 1,039 6,459 3,611 14,179 Deferred acquisition consideration adjustments 2,586 (5,067) 11,003 (8,979) (457) (7,643) 2,073 1,943 9,030 5,403 (4,600) 2,312 2,803 41,672 42,187 Distributions from non-consolidated affiliates 20 11 478 270 779 — 31 (202) 2,219 2,048 (14) 1,079 208 902 2,175 Other items, net 122 (68) 7,346 479 7,879 1,626 6,594 705 349 9,274 2,416 3,895 6,208 18,725 31,244 Adjusted EBITDA (1) $ 7,824 $ 42,954 $ 59,829 $ 50,844 $ 161,451 $ 21,474 $ 46,437 $ 49,205 $ 57,037 $ 174,153 $ 39,568 $ 36,161 $ 54,058 $ 47,545 $ 177,332 (1 )Adjusted EBITDA is a non-GAAP financial measure. See appendix for the definition. Note: Actuals may not foot due to rounding

23 RECONCILIATIONS 2019 2020 Q1 Q2 Q3 Q4 YTD Q1 Q2 Q3 Q4 YTD NON-GAAP ACQUISITIONS (DISPOSITIONS), NET GAAP revenue from current year acquisitions $ — $ 698 $ 1,347 $ 1,396 $ 3,441 $ — $ — $ — $ — $ — GAAP revenue from prior year acquisitions (1) 15,685 1,519 1,109 291 18,604 — — — — — Foreign exchange impact — — 470 (248) 222 (248) — — — (248) Contribution to organic revenue (2) (4,008) (440) (2,185) (1,694) (8,327) (411) — — — (411) Prior year revenue from dispositions (3) (1,825) (5,995) (3,178) (4,505) (15,503) (5,024) (4,106) (4,076) (4,447) (17,653) Non-GAAP acquisitions (dispositions), net $ 9,852 $ (4,218) $ (2,437) $ (4,760) $ (1,563) $ (5,683) $ (4,106) $ (4,076) $ (4,447) $ (18,312) OTHER ITEMS, NET Severance and other restructuring expenses $ — $ 6,703 $ 705 $ — $ 7,408 $ 1,334 $ 2,969 $ 3,270 1,072 8,645 Strategic review process costs 1,626 (109) — 349 1,866 1,082 926 2,938 17,653 22,599 Total other items, net $ 1,626 $ 6,594 $ 705 $ 349 $ 9,274 $ 2,416 $ 3,895 $ 6,208 $ 18,725 $ 31,244 CASH INTEREST, NET & OTHER Cash interest paid $ (1,629) $ (30,014) $ (882) $ (29,698) $ (62,223) $ (145) $ (28,591) $ (575) $ (28,441) $ (57,752) Bond interest accrual adjustment (14,625) 14,625 (14,625) 14,625 — (14,625) 13,894 (14,035) 14,376 (390) Adjusted cash interest paid (16,254) (15,389) (15,507) (15,073) (62,223) (14,770) (14,697) (14,610) (14,065) (58,142) Interest income 149 138 165 162 614 114 190 114 99 517 Total cash interest, net & other $ (16,105) $ (15,251) $ (15,342) $ (14,911) $ (61,609) $ (14,656) $ (14,507) $ (14,496) $ (13,966) $ (57,625) CAPITAL EXPENDITURES, NET Capital expenditures $ (3,606) $ (4,317) $ (5,863) $ (4,810) $ (18,596) $ (1,546) $ (2,144) $ (24,187) $ (9,426) $ (37,303) MISCELLANEOUS OTHER DISCLOSURES Net income attributable to the noncontrolling interests $ 429 $ 3,043 $ 7,265 $ 5.419 $ 16.156 $ 791 $ 3,101 $ 10,728 $ 7,154 $ 21,774 Cash taxes $ 1,677 $ 1,817 $ 137 $ (1,335) $ 2,296 $ 849 $ 1,717 $ 134 $ 5,246 $ 7,946 (1) GAAP revenue from prior year acquisitions for 2019 relates to acquisitions which occurred in 2018. (2) Contributions to organic revenue growth (decline) represents the change in revenue, measured on a constant currency basis, relative to the comparable pre-acquisition period for acquired businesses that is included in the Company's organic revenue growth (decline) calculation. (3) Prior year revenue from dispositions reflects the incremental impact on revenue for the comparable period after the Company's disposition of such disposed business, plus revenue from each business disposed of by the Company in the previous year through the twelve month anniversary of the disposition. Note: Actuals may not foot due to rounding.

24 AVAILABLE LIQUIDITY (US$ in millions) December 31, 2020 December 31, 2019 Commitment Under Facility $ 211.5 $ 250.0 Drawn — — Undrawn Letters of Credit 18.7 4.8 Undrawn Commitments Under Facility(1) $ 192.8 $ 245.2 Total Cash & Cash Equivalents 60.8 106.9 Liquidity $ 253.6 $ 352.1 (1) Subject to available borrowings under the Credit Facility. Note: Actuals may not foot due to rounding

25 CURRENT CREDIT PICTURE Current Debt Maturity Profile (5)$211.5 million Credit Facility Covenants (1) (US$ in millions) December 31, 2020 Covenants I. Total Senior Leverage Ratio (0.02) Maximum per covenant 2.00 II. Total Leverage Ratio 4.42 Maximum per covenant 6.25 III. Fixed Charges Ratio 2.52 Minimum per covenant 1.00 IV. Covenant EBITDA (2) $190.1 Minimum per covenant $120.0 Debt Calculation Total Senior Leverage, net (3) $(3.1) Net Debt (4) $840.1 (1) These ratios and measures are not based on generally accepted accounting principles and are not presented as alternatives measures of operating performance or liquidity. Some of these ratios and measures include, among other things, pro forma adjustments for acquisitions, one-time charges, and other items, as defined in the Credit Agreement. They are presented here to demonstrate compliance with the covenants in the Credit Agreement, as non-compliance with such covenants could have a material adverse effect on the Company. (2) Covenant EBITDA is a measure that includes pro forma adjustments for acquisitions, one-time charges, and other items, as defined in the Credit Agreement. (3) Total Senior Leverage is a measure that includes borrowings under the Credit Agreement, outstanding letters of credit, less cash held in depository accounts, as defined in the Credit Agreement (4) Net Debt is a measure that includes borrowings under the Credit Agreement, the Senior Notes, other outstanding debt and letters of credit, less cash held in depository accounts, as defined in the Credit Agreement. Net Debt does not include Deferred Acquisition Consideration with the exception of certain fixed components ($0.3 million as of December 31, 2020), and it does not include minority interest. (5) Based on borrowings as of December 31, 2020. Excludes letters of credit, and Deferred Acquisition Consideration. Note: Actuals may not foot due to rounding

26 DEFINITION OF NON-GAAP FINANCIAL MEASURES In addition to its reported results, MDC Partners has included in its earnings release and supplemental management presentation certain financial results that the Securities and Exchange Commission defines as "non-GAAP financial measures." Management believes that such non-GAAP financial measures, when read in conjunction with the Company's reported results, can provide useful supplemental information for investors analyzing period to period comparisons of the Company's results. Such non-GAAP financial measures include the following: Organic Revenue: Organic Revenue: “Organic revenue growth” and “organic revenue decline” refer to the positive or negative results, respectively, of subtracting both the foreign exchange and acquisition (disposition) components from total revenue growth. The acquisition (disposition) component is calculated by aggregating prior period revenue for any acquired businesses, less the prior period revenue of any businesses that were disposed of during the current period. The organic revenue growth (decline) component reflects the constant currency impact of (a) the change in revenue of the partner firms which the Company has held throughout each of the comparable periods presented, and (b) “non- GAAP acquisitions (dispositions), net”. Non-GAAP acquisitions (dispositions), net consists of (i) for acquisitions during the current year, the revenue effect from such acquisitions as if the acquisition had been owned during the equivalent period in the prior year and (ii) for acquisitions during the previous year, the revenue effect from such acquisitions as if they had been owned during that entire year (or same period as the current reportable period), taking into account their respective pre-acquisition revenues for the applicable periods, and (iii) for dispositions, the revenue effect from such dispositions as if they had been disposed of during the equivalent period in the prior year. Net New Business: Estimate of annualized revenue for new wins less annualized revenue for losses incurred in the period. Adjusted EBITDA: Adjusted EBITDA is a non-GAAP financial measure that represents Net income (loss) attributable to MDC Partners Inc. common shareholders plus or minus adjustments to operating income (loss) plus depreciation and amortization, stock-based compensation, deferred acquisition consideration adjustments, distributions from non-consolidated affiliates, and other items, net which includes items such as severance expense and other restructuring expenses, including costs for leases that will either be terminated or sublet in connection with the centralization of our New York real estate portfolio. Covenant EBITDA: Covenant EBITDA is a measure that includes pro forma adjustments for acquisitions, one-time charges, permitted dispositions and other items, as defined in the Credit Agreement. We believe that the presentation of Covenant EBITDA is useful to investors as it eliminates the effect of certain non-cash and other items not necessarily indicative of a company’s underlying operating performance. In addition, the presentation of Covenant EBITDA provides additional information to investors about the calculation of, and compliance with, certain financial covenants in the Credit Agreement. Included in the Company’s earnings release and supplemental management presentation are tables reconciling MDC Partners’ reported results to arrive at certain of these non-GAAP financial measures.

MDC Partners One World Trade Center, Floor 65 New York, NY 10007 646-429-1800 www.mdc-partners.com