MARKWEST ENERGY PARTNERS L P

CUSIP: 570759100 Class: UNIT LP PARTN

BLAIR WILLIAM & CO/IL's Holding History (CIK: 0000902367)

Note: Option positions (PUT/CALL) are excluded.

Q3 2015
Shares 49,316 Value ($000) $2,116 Avg Close — Range —
Q2 2015
Shares 48,175 Value ($000) $2,715 Avg Close — Range —
Q1 2015
Shares 46,405 Value ($000) $3,067 Avg Close — Range —
Q4 2014
Shares 46,600 Value ($000) $3,131 Avg Close — Range —
Q3 2014
Shares 11,785 Value ($000) $905 Avg Close — Range —
Q2 2014
Shares 10,910 Value ($000) $780 Avg Close — Range —
Q1 2014
Shares 4,815 Value ($000) $314 Avg Close — Range —
Q4 2013
Shares 4,355 Value ($000) $287 Avg Close — Range —
Q3 2013
Shares 4,355 Value ($000) $314 Avg Close — Range —
Q2 2013
Shares 4,755 Value ($000) $317 Avg Close — Range —