X0306 4 2014-02-05 0 0001166036 MARKWEST ENERGY PARTNERS L P MWE 0001526751 Rosson Paula L 1515 ARAPAHOE STREET TOWER 1 SUITE 1600 DENVER CO 80202 0 1 0 0 SVP/Chief Accounting Officer Common Units 2014-02-05 4 A 0 500 0 A 22924 D Represents a phantom unit, which is a restricted unit that entitles the reporting person to receive a common unit upon the vesting of thephantom unit. Under the grant agreement, the settlement of the phantom units occurs automatically as the phantom units vest, which results inadeemed automatic expiration of the vested portion of the phantom units upon settlement. These phantom units vest one-third a year on January31, 2015, 2016 and 2017. Amount of securities beneficially owned following the reported transaction(s) includes Common Units owned and Restricted Units subject tovarying vesting terms. /s/ Sean M McKendry as POA for Paula L Rosson 2014-02-07