X0306 4 2016-08-23 0 0001158172 COMSCORE, INC. SCOR 0000806968 WPP plc 27 FARM STREET LONDON X0 W1J 5RJ UNITED KINGDOM 0 0 1 0 0001636586 Cavendish Square Holding B.V. LAAN OP ZUID 167 3072 DB ROTTERDAM P7 NETHERLANDS 0 0 1 0 Common Stock 2016-08-23 4 P 0 60000 27.5228 A 11054696 I See Footnote Common Stock 2016-08-24 4 P 0 7639 28.302 A 11062335 I See Footnote Common Stock 2016-08-24 4 P 0 12838 28.8216 A 11075173 I See Footnote Common Stock 2016-08-24 4 P 0 39523 29.5694 A 11114696 I See Footnote The price reported in column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $26.91 to $27.82, inclusive. The reporting persons undertake to provide to the SEC, comScore, Inc., or any securityholder of comScore, Inc., upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (1), (4), (5) and (6) to this Form 4. These shares include a total of 3,493,571 shares of Common Stock of the Issuer that were transferred in February and March 2016 to Cavendish Square Holding B.V. (see Footnote 3 below) ("Cavendish") by WPP Luxembourg Gamma Three S.a r.l., a wholly-owned subsidiary of WPP plc that WPP plc owns indirectly through a series of intervening holding companies, in order to consolidate WPP plc's indirect holdings of Issuer shares (the "Consolidation"). The Consolidation effected only a change in the form of ownership for WPP plc and was exempt from reporting pursuant to Rule 16a-13. These shares are owned directly by Cavendish, which is a wholly-owned subsidiary of WPP plc that WPP plc owns indirectly through a series of intervening holding companies. WPP plc is an indirect beneficial owner of the reported securities. The price reported in column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $27.45 to $28.44, inclusive. The price reported in column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $28.45 to $29.44, inclusive. The price reported in column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $29.45 to $29.78, inclusive. WPP plc, By: /s/ Paul Richardson, Global Finance Director 2016-08-25 Cavendish Square Holding B.V., By: /s/ A. van Heulen-Mulder, Managing Director 2016-08-25