X0306 5 2016-12-31 0 0 1 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 2016-09-09 4 P 0 30000 30.23 A 11319363 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 $29.92 to $30.63, 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 above. This number reflects the correction of a one share error in the Reporting Owners' prior Form 4. 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. WPP plc, By: /s/ Paul Richardson, Global Finance Director 2018-04-06 Cavendish Square Holding B.V., By: /s/ A. van Heulen-Mulder, Managing Director 2018-04-06