X0202 4 2006-03-17 0 0001166036 MARKWEST ENERGY PARTNERS L P MWE 0001280468 YOUNG DAVID LEE C/O MARKWEST ENERGY PARTNERS, L.P. 1515 ARAPAHOE ST. TWR 2, STE 700 DENVER CO 80202 0 1 0 0 SVP, Corporate Svcs Common Units 2006-03-17 4 F 0 45 45.65 D 1334 D Common Units 2006-03-30 4 S 0 91 44.78 D 1243 D Common Units 2006-08-28 4 A 0 500 0 A 1743 D Phantom Units 2006-08-28 4 M 0 500 0 D Common Units 500 270 D 1 for 1 Under this phantom unit agreement, the settlement of the phantom units occurs automatically as the phantom units vest, which results in a deemed automatic expiration of the vested portion of the phantom units upon settlement. The phantom units vest over a period of three years, with 1/3 vesting at January 31 of each anniversary year. The vesting may be accelerated in certain instances if the issuer achieves certain unitholder distribution targets. Amount of securities beneficially owned following reported transaction(s) includes Common Units owned and Restricted Units subject to varying vesting terms. /s/ Sean M. McKendry as POA for David Lee Young 2006-11-17