MARKWEST ENERGY PARTNERS L P

CUSIP: 570759100 Class: UNIT LP PARTN

DRIEHAUS CAPITAL MANAGEMENT LLC's Holding History (CIK: 0000938206)

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

Q1 2015
Shares 125,208 Value ($000) $8,276 Avg Close — Range —
Q4 2014
Shares 124,708 Value ($000) $8,379 Avg Close — Range —
Q3 2014
Shares 115,611 Value ($000) $8,881 Avg Close — Range —
Q4 2013
Shares 109,924 Value ($000) $7,269 Avg Close — Range —
Q3 2013
Shares 201,344 Value ($000) $14,543 Avg Close — Range —
Q2 2013
Shares 193,044 Value ($000) $12,905 Avg Close — Range —